No one is actually in charge. It is only by custom that what @bycoleman says is true.
You cannot change tags on posts older than 7 days, and you can never delete the first tag (as i becomes a part of the URL of the post itself.
What @bycoleman says is true, but you should not be worried. No one is keeping track. (Except for bots like this)
Got it, thanks for the info @improv. I mean, you're here, why not give a crack at the contest?
@improv is right in that Steemit is a decentralized system, so no one is actually in charge. @steemcleaners does keep track though and if you're reported, they can flag you for it.
The intent is so new people can introduce themselves. If people just post random stuff, then the newbies don't get seen. That's why they consider it abuse.
Check out my id number :p