You have NO idea how sick I am of telling people about this that get infected with it. Yes, I know how old this info is.
Don't follow any links that say you were in a video unless you ask the person that posted it on your wall. If you go to it and it says you need to "update your Flash player". Don't do it!
Don't go to a site if they IM it to you unless you are talking or kind of talking to them that day.
Koobface is a worm that has been going around Facebook and getting into people computers. Mainly by directing you to a website that has you "update your Flash player". That update is the worm in which infects your PC and it sends people links through Facebook so they can get infected as well. If you send something that you didn't send, that's a major symptom of the Koobface worm.
No, the worm didn't send this.
This is what the "update" looks like.
For more info, go to Wikipedia.
http://en.wikipedia.org/wiki/Koobface