Twitter is a real good networking site. With twitters growing popularity there is increase in number of bots . Twitter bots spam a lot. Following a twitter bot is very risky (in the sense it reduces value on ur timeline spamming it). But all bots are not spammy some twitter bots are cute and fun, you will love following them
@ghantaghar this is a indian bot which tweets time on twitter (IST) When you are tweeting you lose track of time then you can follow this bot which will remind you how much time you are wasting on twitter.
@woot This is a bot for the popular website where you can track daily Woot : One Day, One Deal (SM) deals.
@snaptweet Follow this bot which allows you to post flickr photos on twitter
@TrackThis helping you track fed ex and DHL packages on twitter
@gcal: this is twitter calendar where you can add events to goggle calendar just by tweeting