Twitter API returning results that do not respect the arrow of time
twitterbug.quietbabylon.com
twitterbug.quietbabylon.com
along with other related stories listed here: http://ansible.co.uk/books/dkod.html
Maybe all the people I follow on Twitter but don't know in real life aren't real, but merely a series of pre-generated messages, served up by a scheduler.
Replies are done with fancy natural language processing and monitoring of what's popular on the web. Retweets and follows are triggered by your social graph and cookie history.