I have a sidebar which shows me which friends are online and what game tey are playing - I found the option configure or disable that as well.

What I have not found yet is a setting to disable this information to be shared from me with my friends . Kind of a privacy mode. Is there something like that?

Sure is: click on your avatar at the top of Galaxys sidebar and then "Account Management", there you can go to "Privacy" and change this, amongst other settings. On the way to this you can also set yourself to be "invisible".

This is assuming you use Galaxy 2.0, this all existed in 1.2 as well, I just don't know where exactly.

Oh, and if you wish to be entirely stealhy, you don't even need to use Galaxy unless you play online MP. Just launch the games from their executables in their folders without starting Galaxy first. You can also use the "offline installers" if you prefer no client at all, but you need to download them manually and they insist on unpacking to the windows temp folder, so if you, like me, don't have sufficient space on this drive, you can't do that.

thank you - found it