Does Facebook censor comments?

I have a Facebook account mainly just to keep up with old friends and family (they are spread out all over) well anyways I made up this little song about BP and posted it on “What’s on my mind” and it was there for a about a week and I just now noticed it’s gone. Does that go away after a while or did some FB rep censor it and delete it?? All it was was a the Spongebob theme song with the words changed to reflect on the oil spill in the gulf.

it went like this..

OOOOHHHH
Who lives in an oil spill made by BP?
Spongebob Squarepants
Absorbed some of the oil because he lives in the sea
Spongebob Sqarepants
If destroying the ocean is something you wish
Songebob Sqarepants
Then work for BP you’ll kill all the fish
Spongbob Squarepants
Spongebob Sqarepants
Poor Spongebooooob Squarepants*

anyways, it got taken down, and I did not do it…are they really censoring things you post on there now??