There are any number of bots (i.e. robots) on Twitter. These are accounts that are programmed to tweet when they find a certain term. Send a tweet out about iPad and you will immediately see a bunch of spam tweets responding to yours.

I re-tweeted a post about the top WordPress plugins on 3/30, and a friend RT’d it. An account called @DesignEcho re-tweeted  that one and added the hashtag #Design. @DesignEcho is using Twitterfeed (a sure sign of a scheduled tweet). The first instance of the RT was at 6:45pm.

Unfortunately for it, the bot then continued RT’ing its own tweet at 7:16pm,  9:51pm, 11:21pm, and 11:52pm. It looked like this by the end:
evolutionfilesMar 30, 5:36pm via TweetDeck

RT @anitasearchguru @bkmacdaddy: Top 100 #WordPress Plugins – The Best Of The Rest goo.gl/Dvnxt

Design_EchoMar 30, 6:45pm via twitterfeed

RT @evolutionfiles RT @anitasearchguru @bkmacdaddy: Top 100 #WordPressPlugins – The Best Of The Rest ht…

Design_EchoMar 30, 7:16pm via twitterfeed

RT @Design_Echo RT @evolutionfiles RT @anitasearchguru @bkmacdaddy: Top 100 #WordPress Plugins – The Bes.

Design_EchoMar 30, 9:51pm via twitterfeed

Design_EchoMar 30, 10:21pm via twitterfeed

Design_EchoMar 30, 10:52pm via twitterfeed

RT @Design_Echo RT @Design_Echo RT @Design_Echo RT @Design_EchoRT @evolutionfiles RT @anitasearchguru @…