Adding friends to facebook who you don't particularly like, socialize with or think you are friends with.

Creating a profile that is not you, with a fake name and details, possibly for the reason to spy on someone you don't want to know is you

having a fake Facebook account to stalk/check/spy on one's ex, their new partner etc etc

A second Facebook account set up so only your really real friends can see what you really real think.

Another account set up because your primary one has been contaminated by "friends" you work with/for, people who you might talk crap about, etc., but which you can't delete or unfriend for certain reasons.

For example, you work for a company where your boss and other upper management like to find you and friend you, then you're scared to talk crap about said company.

A Facebook account set up under a fake name. Used for snooping, creeping, stalking, or just for shits and giggles.

The usually humorous depictions of a fake facebook page of a famous person, which contains back and forth banter with other affiliated people, status updates, groups etc...

Fat book of rip-off transcriptions of sheet music of all genres. Illegal because the musicians who wrote the music get no royalties.