I have quite a few twitter account and they are usually based on my intended use towards them. Like, 3 are personal accounts and the rest are used to website promotion. I use one single app to manage them all, pretty nice.
It's just FUN what I have analyzed upto now of Twitter...If you have friends, then it's always good to connect with them from any source.
u need to have a huge following base for that .. u can try google wave too .. i heard its gonna be the best!