mchack: But then again it might work in their favor for getting new customers on their site where some might actually buy stuff (I mean why else would they do gog/connect for instance?)
That's exactly my thoughts, one of the reasons is that they need more people who will discover GOG and stay here for good (becoming loyal customers), which is also main point of GOG Connect. Even though they won't get any revenue from Humble Bundle - at least they will be raising awareness of GOG and support charity, which is always a nice thing. Offering free game(s) during sales or special events is basically the same thing, there's always someone new here.
About 6 months ago i asked one of the blues here about working with HB and he kindly replied: "We are friends with Humble, and this idea is something we thought of already, but there are some things we need to tackle first."
I'm sorry for the off-topic.
(no i'm not :p)