As I picked an easy lock, the Steam box popped up in the bottom of my screen and said I had unlocked the 'No fumble tumbler' perk.
Er.. Whassat then?

It's an achievement for picking 25 locks. There are perks though that can be earned by doing challenges like killing 50 mutated animals or whatever. The achievements are something through Steam I think, but you can see all of the challenges in the pipboy.

Lovely, thanks very much. Was wondering why it kept flicking up the other things about kills as well, answered that for me too.