http://www.gog.com/forum/general/the_whats_up_with_gog_connect_thread It's been alive this year too, although for all practical purposes, it has been de-facto cancelled for a long time.
If they have one game there every six months or so, it really doesn't benefit anyone, as the window to react for people who have that one game and know to act during those few days is practically speaking impossible, except for those who actively follow the thing, like the linked thread above.
Presumably that experiment didn't create any additional income on GOG's side, quite possibly it even did the opposite, as buying a game on Steam activated that game also on GOG.
Personally I found GOG Connect to be very useful in some special cases, like when I had some game from IndieRoyale bundles, which later added Steam codes, and then it was possible to re-acquire some of them DRM-free on GOG.
I hope they continue Connect sooner or later, but it really has to be better organised than it was.