Connect is currently NOT live.

Games available:
none

Let's start with some good links:

GOG Connect page (including FAQ):
https://www.gog.com/connect

Issues with GOG Connect?
https://support.gog.com/hc/en-us/articles/115003586109-Problems-with-GOG-Connect-possible-fixes

Original introduction:
https://www.gog.com/news/introducing_gog_connect
https://www.gog.com/forum/general/introducing_gog_connect_8fac8 ← And corresponding thread. This is the main troubleshooting thread.

Common Issues:
GOG can't read your Steam library
» Make sure that both your Steam profile and your Steam games list is set to public.
It can't be my Steam settings—it's worked before, and I haven't changed anything!
» Steam has been reported as having changed the settings by itself. I suspect when it added a separate privacy option for the games list, it also set that option as private by default, thus hiding the games list from GOG for all that haven't fiddled with their privacy settings since.
But it worked for some of the games, but not all. How can that be?
» It's possible that GOG had managed to scan your library before a change in privacy settings made it impossible, so GOG is aware of the games that was in your Steam library at that point, but not any new ones you've added since. It is also possible that there is some issue with the particular games in question; sometimes there are multiple versions (with differing Steam ID) of what is essentially the same game. If GOG hasn't added all applicable versions, this can cause GOG to fail to recognise you as the owner of said game.
Refresh button not working
» It can take some time for it to work. Additionally make sure GOG can read your stem library as stated above. Also keep in mind that you can only do a refresh once every two hours, so if you changed your profile and games list setting to 'public' AFTER you refreshed, you may have to wait for a couple of hours before you can successfully refresh again.

Misc GOG Connect questions:
Will games previously featured on GOG Connect return?
» Whilst we cannot be sure, it has happened in the past.
Can I move games from GOG to Steam?
» No, you can't.
Does GOG Connect work for DLC?
» Due to limitations in Steam's API, it doesn't.
https://www.gog.com/forum/general/why_you_cant_connect_to_get_your_games_from_steam/post1
https://www.gog.com/forum/general/gog_connect_my_steam_account_profile_privacy_settings
https://www.gog.com/forum/general/gog_connect_steam_refund
https://www.gog.com/forum/general/what_information_is_shared_w_steam_w_gog_connect

There were also a veritable flood of troubleshooting threads regarding gog connect when it first showed up, and I decided not to include the majority of those; basically the following sums up my experience when GOG Connect was first introduced:

https://www.gog.com/forum/general/gogsteam_connect_feature_will_work_give_it_time_and_patience/page1

Past GOG Connect offers
Due to lack of space in the OP, I moved the list here.

Other similar offers

If you have an original game key from a boxed copy of the following games, you can claim a GOG copy here:
Eador: Genesis
S.T.A.L.K.E.R.: Shadow of Chernobyl
S.T.A.L.K.E.R.: Call of Pripyat
S.T.A.L.K.E.R.: Clear Sky
Mount & Blade: With Fire & Sword
Mount & Blade: Warbands
Torchlight
Torchlight II

Reclaim your Game: Master of Orion 1, 2 & 3
Requires a boxed copy and the following steps:
1. Write down your GOG.com registration email on a piece of paper
2. Take a photo of the game box and/or the CDs together with the email address. Please note that the game and your GOG.com registration email need to be clearly visible in the picture.
3. Send the photo to moo_reclaim@gog.com

If you already own any PC or Mac edition of either The Witcher or The Witcher 2, you can redeem your free backup PC copy here.
----------------------------
The original purpose of the thread: direct these to this:
http://techraptor.net/content/gog-connect-continue-future
https://www.reddit.com/r/pcgaming/comments/4swx1e/what_happened_to_gog_connect/d5d3966
It's old news by now, however.
----------------------------

Have I missed anything? If there have been more news regarding gog connect, any other good link on gog connect you know about, or you miss your favourite 'what happened to gog connect' thread let me know in a reply below and I will add it to the OP.

Finally! Someone took the time to compile them all!

I'd uprep you twice if I could. :D


PS: As a suggestion, you could number the threads, in order to get a better sense of the scale of the tragedy. :P

Thank you. :)

I don't know quite what got into me, I just saw yet another of these threads and thought "Right, that's it".

Edit:
I'm adding the list of 'What happened to GOG Connect' threads here to make the main post a little easier to overview for people with general GOG Connect questions.

NOTE: This list is no longer being maintained, as the issue of countless people coming to the forums to ask if or when GOG Connect is coming back has slowed to a mere trickle as of late. In effect, I no longer see much point in maintaining the following list.

Others who've had more or less the same question (i.e. why people are getting fed up with the question):
https://www.gog.com/forum/general/happened_to_gogconnect
https://www.gog.com/forum/general/whatever_happened_to_gogconnect
https://www.gog.com/forum/general/question_about_gog_connect_2
https://www.gog.com/forum/general/steam_transfer_of_keys_to_gog
https://www.gog.com/forum/general/steam_connect_trouble
https://www.gog.com/forum/general/are_certain_games_we_own_on_steam_still
https://www.gog.com/forum/general/what_happened_to_gog_connect_3
https://www.gog.com/forum/general/when_will_we_be_getting_more_games_from_connect
https://www.gog.com/forum/general/what_happened_to_gog_connect_2
https://www.gog.com/forum/general/what_happened_to_gog_connect_1
https://www.gog.com/forum/general/gog_connect_3
https://www.gog.com/forum/general/is_that_it_for_gog_connect
https://www.gog.com/forum/general/no_more_connect_games
https://www.gog.com/forum/general/gog_connect_are_you_seeing_new_games
https://www.gog.com/forum/general/so_what_happed_to_gog_steam_connect
https://www.gog.com/forum/general/have_they_forgotten
https://www.gog.com/forum/general/steam_games
https://www.gog.com/forum/general/what_happened_to_gog_connect
https://www.gog.com/forum/general/gog_connect_2
https://www.gog.com/forum/general/gog_connect_does_not_connect
https://www.gog.com/forum/general/gog_connect_still_supported
https://www.gog.com/forum/general/are_there_no_games_currently_on_gog_connect
https://www.gog.com/forum/general/gog_connect_gone
https://www.gog.com/forum/general/what_happened_to_that_steam_connect_bonus
https://www.gog.com/forum/general/i_cant_find_the_list_of_games_that_if_you_buy_on_steam_you_get_free_on_gog
https://www.gog.com/forum/general/gog_connect_1
https://www.gog.com/forum/general/gog_connect_list_of_games_supported
https://www.gog.com/forum/general/gog_connect_didnt_last_very_long
https://www.gog.com/forum/general/is_gog_connect_a_data_mining_scam
https://www.gog.com/forum/general/what_are_the_odds_that_gog_connect_ends_up_being_a_one_time_thing // the OG 'no more connect games' thread.

Yay. Great work!

I think that should be a sticky.

Thank you.

Thank you for creating this thread!

Somehow, i thought that there were more of those...

Does this give me permission to go off on people when they start new Connect threads?

+1 for creating this thread.

Keep your pants zipped up..

No, if they are new to the forums. You could be nice and redirect them here. What happened to science guy? (back to the future avatar)

+1 : https://www.gog.com/forum/general/community_stickies_compendium_40/post49

Another one :P (even though what the OP is asking is to transfer GOG games to Steam, instead of the other way round...)

Thanks, I put it in the misc section as more people are bound to ask that question. :)

EDIT:
Due to the original post running out of space, here are the first set of offers of the past:

Available from 1 June 2016 until 8 June:

Breach & Clear: Deadline
Bit.Trip Runner
Braid
Breach & Clear
Broken Sword: Director's Cut
FTL: Advanced Edition
Galactic Civilizations III
The Incredible Adventures Of Van Helsing: Final Cut
Mount & Blade
Project Zomboid
Saints Row 2
Shadowrun Returns
Sherlock Holmes: Secret Of The Silver Earring
Surgeon Simulator 2013
The Witcher: Enhanced Edition
To The Moon
Trine Enchanted Edition
Two Worlds
Unreal Gold
Unreal Tournament Goty
The Witness
VVVVVV
Xenonauts

Available from 7 June 2016 until 13 June:

Kona
Defender's Quest
Door Kickers

Available from 25 August 2016 until 2 September:

Master of Orion 1 & 2
Master of Orion 3

Available from 26 September 2016 until 2 October:

AI War: Fleet Command
Anno 1404: Gold Edition
Baldur's Gate: Enhanced Edition
Dex
Hotline Miami
Shadow Warrior (2013)
Incredible Adventures of Van Helsing: Final Cut
Cossacks Anthology
Hot Tin Roof: The Cat that Wore the Fedora
The Last Federation
OlliOlli
Teslagrad
The Masterplan
Two Worlds Epic Edition
X: Gold
X Rebirth
Ziggurat

Available from 7 November until 14 November:

Alien Shooter + Expansions
Broken Sword: Director's Cut
Broken Sword 2: Remastered
Eador: Genesis
Frozen Cortex
Frozen Synapse
Huniepop
Metro 2033 Redux
Moto Racer
Moto Racer 2
Moto Racer 3 Gold Edition
Risk of Rain
Sins of a Solar Empire®: Rebellion Ultimate Edition | <i>There were issues aplenty with this one&ndash;GOG set up a temporary mail adress to deal with all support tickets.</i>
Starbound
Vangers
Worms World Party Remastered
Zombie Shooter
Long term offers introduced during the sale (lasting until 7 December 11:00 UTC):
Witcher: Enhanced Edition, The
Witcher 2: Assassins of Kings, The - Enhanced Edition
Witcher Adventure Game, The

Available from 22 November until 1 January:

Limbo

Available from 5 December until 12 December:

Atlantis 2: Beyond Atlantis
Ball, The
Costume Quest
DEFCON
Etherlords
Etherlords 2
Gorky 17
Knock-Knock
PixelJunk™ Shooter
Realms of Arkania 1+2
Realms of Arkania 3
Stacking
Still Life
Total Annihilation: Commander Pack
Tropico Reloaded
Tropico 3 Gold Edition
Unmechanical: Extended
Walking Dead: Season 2, The

Available from April 20 (12 AM UTC) until April 27, 10 AM UTC:

Saints Row 2
Saints Row: The Third - The Full Package
Saints Row IV: Game of the Century Edition
Saints Row: Gat out of Hell

Available from May 10 to May 24.

Renowned Explorers: International Society

Available from June 6 to June 20

AI War: Fleet Command
Amnesia: The Dark Descent
Ascendant
Brutal Legend
Cosmonautica
Darwinia
Deathtrap
DEFCON
Democracy 3
Deponia
Depths of Peril
Downwell
Dropsy
Earth 2140 Trilogy
Earth 2150 Trilogy
Earth 2160
Evoland
Frozen Cortex
Frozen Synapse
Gratuitous Space Battles 2
La-Mulana
Last Federation, The
Men of War
Metrocide
Not a Hero
Puddle
Redshirt
Reigns
Renowned Explorers: International Society
Reus
Shadowgrounds
Shadowgrounds Survivor
Sir, You Are Being Hunted
Stacking
Tharsis
Time Gentlemen, Please! + Ben There, Dan That!
Unepic
Vertical Drop Heroes HD
The Walking Dead: Season 1
X2: The Threat
Game added on June 14: War for the Overworld

Torchlight special, between 2017-10-11 – 2017-10-14:

Torchlight
Torchlight II

Halloween sale 2017, between 2017-10-26 – 2017-11-02:

Amnesia: A Machine For Pigs
Amnesia: The Dark Descent
Bad Mojo Redux
Corpse Party
Darkwood
Deadly Premonition: Director's Cut
Dracula 4+5
Gabriel Knight: Sins of the Fathers - 20th Anniversary
Hand of Fate
Knock-Knock
The Last Door: Collector's Edition
The Last Door: Season 2 Collector's Edition
Layers of Fear
Nosferatu: Wrath of the Malachi
>observer_
Pathologic Classic HD
POSTAL: Classic and Uncut
Realms of the Haunting
Shattered Haven
SKYHILL
Smugglers V: Invasion
SOMA
STASIS
Sunless Sea
The Void
The Walking Dead: Season 1
The Walking Dead: Season 2
The Walking Dead: Michonne - A Telltale Miniseries
The Walking Dead: A New Frontier

Syberia giveaway, between 2017-11-09 – 2017-11-13:

Syberia 1
Syberia 2

Winter sale 2017, between 2017-12-12 – 2017-12-26:

Baldur's Gate: Enhanced Edition
Darkest Hour: A Heart of Iron Game
The Final Station
For the Glory: A Europa Universalis Game
Homeworld: Deserts of Kharak
Homeworld® Remastered Collection
INSIDE
Limbo
>observer_
Outlast
Perception // Removed at some stage. People have been reporting various games showing up and disappearing this time around.
Punch Club
Rebel Galaxy
Rogue Wizards
Sengoku
Sunless Sea
Tahira: Echoes of the Astral Empire
Zombies Night Terror
Games added 21-12:
Batman: The Telltale Series
The Walking Dead: Season 1
The Wolf Among Us
Games added 22-12:
Eador. Masters of the Broken World
Man O' War: Corsair - Warhammer Naval Battles
The Solus Project
The Whispered World: Special Edition
Zombie Shooter 2
Game added ??-12:
Baldur's Gate II: Enhanced Edition

Greet the Year of the Dog sale, between 2018-02-13 – 2018-02-20 (11 PM UTC):

AI War Collection
HuniePop
Kim
Mount & Blade
Orwell
Pirates! Gold Plus
The Sexy Brutale
Tempest
Torchlight
Tropico 4
Unreal Tournament GOTY

Summergaming Sale, between 2018-06-04 – 2018-06-18 (10 PM UTC):

Amnesia: A Machine For Pigs
Banished
The Banner Saga
FTL: Advanced Edition
Grim Dawn - EDIT: Only until the 6th of June, 1PM UTC.
Hotline Miami 2: Wrong Number
Jotun: Valhalla Edition
Kingdom: New Lands
Legend of Grimrock
Prison Architect
Psychonauts
Starpoint Gemini 2
Tempest
EDIT: Omerta: City of Gangsters Gold Edition (Available to some, but not all, users, it seems) EDIT: I read somewhere that this was a mistake, and Omerta wasn't supposed on GOG Connect. I don't recall where I read it though...

Back to School 2018 sale, between 2018-09-04 – 2018-09-10 (10 pm UTC):

For the Glory: A Europa Universalis Game
King of Dragon Pass
Knights of Pen and Paper +1 Edition
MDK
Toonstruck
Tempest
Late addition: Shadowrun Returns

Winter sale 2018 offers, available between 2018-12-13 – 2019-01-03:
Age of Wonders 3 (2018-12-13 – 2018-12-20)
I Have No Mouth And I Must Scream (2018-12-13 – 2018-12-20)
Oddworld: Abe's Oddysee (2018-12-13 – 2018-12-20)
Shadowrun Returns (2018-12-13 – 2018-12-20)
Shadowrun: Dragonfall - Director's Cut (2018-12-13 – 2018-12-20)
Shadowrun Hong Kong - Extended Edition (2018-12-13 – 2018-12-20)
Trine Enchanted Edition (2018-12-13 – 2018-12-20)
Forgotten Anne (2018-12-18 – 2018-12-20) ~ Late addition. Added upon game release.
-
Convoy (2018-12-20 – 2018-12-27)
Enigmatis: The Ghosts -of Maple Creek (2018-12-20 – 2018-12-27)
Hard West (2018-12-20 – 2018-12-27)
Knight's of Pen and Paper +1 Edition (2018-12-20 – 2018-12-27)
Syberia (2018-12-20 – 2018-12-27)
-
Divine Divinity (2018-12-27 – 2019-01-03)
Dustforce DX (2018-12-27 – 2019-01-03)
Descent (2018-12-27 – 2019-01-03)
Europa Universalis: Rome Gold (2018-12-27 – 2019-01-03)
Order of Battle: World War II (2018-12-27 – 2019-01-03)
Panzer Corps (2018-12-27 – 2019-01-03)
Tharsis (2018-12-27 – 2019-01-03)
Two Worlds Epic Edition (2018-12-27 – 2019-01-03)

Stellaris Summer Sale offer, only available for a few hours 2019-06-04 due to technical issues:
Stellaris

AI War 2 release offer, available between 2019-10-22 – 2019-11-05:
AI War 2

Hedon realease offer, available between 2019-11-05 – 2019-11-12:
Hedon

The Winter Sale 2019:
Age of Wonders: Planetfall [2019-12-11 – 2019-12-??]
DUSK [2019-12-11 –2019-12-?? ] // Sorry I missed when the offer ended for these two (it's prior to 21 at least). I haven't been visiting this site quite as regularly as I used to, and you can only see the end date when you've got games you've yet to claim.
Galaxy Trucker: Extended Edition [2019-12-11 – 2020-01-02]
Through the Ages [2019-12-11 – 2020-01-02]
Bad North: Jotunn Edition [2019-12-27 – 2020-01-02]
Chasm [2019-12-27 – 2020-01-02]
Hedon [2019-12-27 – 2020-01-02]

They keep spawning!
https://www.gog.com/forum/general/what_happened_to_gog_connect_2