Whenever I post I read "transferring data from www.facebook.com..." below on the posting window. Since I don't really like facebook I'm curious what connection there might be.

At the bottom of every page GOG has social media buttons that load.

I know, just did not expect it getting data in every post (which does not have such buttons) I make; or see it loading long enough to actually see it loading. ;)

Read.

https://developers.facebook.com/docs/plugins/like-button
https://developers.facebook.com/docs/plugins/share-button

from the left sidebar you get more options.

Yeah, except that it doesn't load any Like button. Only the usual tracking crap 1x1 pixel image.
Same goes with twitter and google. It loads only the scripts, no image.

OP. If you use those services block them on any 3rd party website, if not block them everywhere with your adblocker.

Weirdly, even the reply box I'm typing into loads the trackers. Or would, if I weren't blocking them.