Both of my installations (Mac, Xubuntu, both with Oracle Java) are linked now with ProZ.com. But on the Xubuntu side, there pops up a window in regular intervals, showing me what people are working on (and asking me to enter my project).
Is this platform-specific or did I hit any shortcut by accident?
There is an option in that pop-up dialog to turn the automatic pop-up off. You can also do it in Edit > Preferences > Web services tab.