Just wanted to pass a small nugget along. I've used tools like manageflitter, tweepi & done a tone of bulk following. I've even been suspended a few times too. What I'm finding out though is that if you ask people to follow you back most of them will especially if you post things they are interested in. I didn't do it at first but now I pay someone a compliment or and then i end my tweet with "follow back [inserted with their name]?" - And they follow back. I found making a follow back request personal works wonders. I only do this for the accounts I really want to have a connection to though.