Twitter became popular because of its 140 character restriction, orginally designed to fit an SMS.
This restriction promises the follower that everything will be easily digested, but perhaps more important is the benefit to the writer.
Often someone starts a blog, but then quits when every post becomes too long. Too ambitious. Twitter frees the writer of such pressure.
Pressure to be concise is great, but I propose that the 140 char limit is too limiting to express anything interesting. Tweets are dumb.
Instead of microblogging, I propose #milliblogging. You must constrict yourself to (maybe?) 1000 characters - the length of 7 tweets.
Would you join such a site? Would you rather it be an extended Twitter-client or a new community?
#Milliblogging - for people with something to say.
(This post was also tweeted by me on http://www.twitter.com/fnedrik )