Why are so many Twitter users badly behaved?

I looked up the words badly behaved in the Oxford English Dictionary and found this:

badly behaved, adj.

DRAFT ENTRY Sept. 2008  
Brit. /badli bhevd /, U.S. /bædli bhevd /, /bædli bihevd /  [< BADLY adv. + BEHAVED adj. Compare WELL-BEHAVED adj.]

    1. Of a person or animal: that (habitually) violates standards of proper or appropriate behaviour.
    2. Of an object, phenomenon, etc.: having properties that do not conform to an expected, desired, or predictable pattern.

This definition discribes an unruly group of people... and many of them are Twitter users! Yes, I said it. I just don't see why so many Twitter users offer nothing, and I mean nothing, but links to tired affiliate programs without even so much as a bit of humor. Not so much as an interesting anecdote. Not even a comment on the latest current affairs.

You know who you are and I was really hoping to be entertained!

Seriously, though, I'm interested in being inspired to hear more of what someone has to say. Sadly I'm just not inspired as much as I want, or need, to be.

I'd love to hear your comments, criticism included, on this topic.

P.S. OK, so three guys walk into a bar...