I removed some "friends". They were old colleague in a former job.

I added them when it was common to add everyone. What, it's already that ? ohhhh, sorry, I step off the boat :)

I, like most people I guess, add old school friends if they ask, but sometimes their constant stream of rubbish/pointless posts gets too much, or they are racist or bigotted (good word, thanks Gordon Brown!), so they get the Facebook 'chop'.

the only time I've ever pulled any of my friends is when I end a friendship with them. Then again, my Facebook is my closely guarded social App.  you won't find me in search engines and you can't get nosey with my profile.  It's not that I'm up to no good, but Twitter is definitely more anonymous than FB. 

I also use Twitter more because I get a faster response on the things I post.  (I realize I went a tad off topic)

I clean "my friends" list two times by year, especially who don't give news.

Bit of housekeeping every now and then doesn't hurt.

I sometimes clean-up. With Facebook's Lists feature I organize all the people I invite into groups (as soon as I invite them or they accept my invitation) and then only receive messages and updates from the groups I am interested in.

I usually clean up my Friend list when i get annoyed by someone, or just hide them some of the stuff they put is just useless and i barely even know them so i cut them out...