This looks like a new bubble. Why would a Twitter IPO raise so much money? What are its growth prospects? Facebook may be different, but still, it all sounds very crazy.
The thing failed silently and stayed broken for two months, and NOBODY NOTICED: neither he nor any of his "followers" (he had more than a thousand).
So, having found out about the situation, he decided to stop using Twitter altogether.
On LinkedIn I now have to see all the tweets of my "contacts" whenever I log in; this is so annoying that it may push me to quit LinkedIn for this reason alone.
People on Twitter are just copying and pasting news found elsewhere; there is an infinitely small proportion of original content: for one "Shit My Dad Says", there are millions of users who only mulch old content from the likes of Digg (RIP) or Reddit or HN.
Twitter users are not paying attention to one another; they shout in the desert and nobody cares.
This cannot go on forever.
I find Twitter to be very useful because interesting people who I follow post links to interesting stuff. But, not too many fully formed ideas in 140 characters: just links or short funny things, etc.