I was thinking since there's a message board up, will there be a more robust online community in the future? As of now, there's just a message board, but what about profiles, buddy lists, etc.?

I believe this stuff is in the works. In the feature wish list thread, Vandal hinted at some of the upcoming features I believe. Here is a link to his post to help. It would definitely be nice to see some of these things.
http://www.gog.com/en/forum/general/gog_039_s_features_wish_list/perm=4/#p_b_4

I have a few ideas that could help with the community.
An online users list would be nice; I mostly take it for granted on any other bulletin board I visit, but when we're talking about getting a multiplayer game set up, well, it does pay to know who is online and who isn't.
More robust profiles/accounts would also be appreciated. I'd actually prefer if there isn't a signature bar, but a text box like "Information" or "About Me" that shows up when you access a user's profile would be cool.
The "people with the most Rep" on the forums page is interesting, but I'm not sure what determines a user's Rep, if it's between good reviews, good forum posts, answering forum questions, etc.
EDIT: Well, I found (mostly) what determines a user's rep; it was kind of tucked away (sneaky GOG) in the FAQs and it's still open-ended, but it's nice to see that there aren't any loose ends with this launch.

The link above in my previous post has one of the developers of the site talking about many of the features you just mentioned.
In regards to reputation, it helps show how respected and known you are within the community. You earn rep through spending time on the forums, receiving positive ratings and helping others. Supposedly, those will very high rep may garner a surprise, but no mention of what it may be. Essentially, rep is a good way to weed out the offensive and misbehaving members, and rewarding the ones who try their best to contribute to the community.