Nirth: I agree some are ridiculously hard but it's easy to make them recognizable by a human but not by a spam bot, of course they won't work against human spammers.
And I only meant for posting a review, not posting on the forum. Do you post reviews that often that one CATPCHA per review would bother you? (assume that they would use a picture of letters and numbers that you realize what they're in a second after your browser rendered it)
Anyway, I think the filter between GOG version/not is more important because it would be fun to find people with nostaglia glasses who claim they don't have them, mainly because I usually read reviews for amusement, never as evidence for a potential good purchase.
Actually I never post reviews. I just hate captcha's on principle and in practice.
On principle it is another example of the majority of innocent people being inconvenienced as a result of the minority of guilty.
In practice I seriously do have a problem with them - perhaps its some weird form of dyslexia, or just an age thing - I have had accounts locked simply because I can't get three of them in a row.