People who rant on the basis that "You're using the service in a different way to me" is the same thing as "You're abusing the service" are... well, they annoy me, lots.
Clearly this is written by someone who has never used IRC.
If you don't like the type of messages that some people are sending on twitter, then don't follow them. Send messages to your IM client instead of your phone. Read the FAQ, especially the section about commands - you would be particularly interested in "leave jane".
Whatever. If you don't like it, don't use it - but don't complain that people who aren't using it in a way that's convenient to use is "abuse".
Note to Twitter peoples: Channels! We need channels!