Here are some interesting articles on Twitter and how some social media experts use it. Remember that these guys live on the social media sites, so may not be the best way for us to use it, but does answer the question, how do they read all the stuff from the people the follow (short answer: they don’t):

How Guy Kawasaki Twitters:
http://blog.guykawasaki.com/2009/07/how-i-tweet-just-the-faqs.html

How Chris Brogan Twitters:
http://www.chrisbrogan.com/how-i-tweet-a-faq/

And here’s a service to let a group of people coordinate their twittering on one account (like for a company):
http://www.readwriteweb.com/archives/cotweet_opens_public_beta_now_you_can_tweet_like_starbucks.php