Check out this really cool site!! You can use it to see who all is following you on twitter that you do not follow and who you follow who does not follow you. I went through and there were 55 people who follow me I was not following. I try to keep up with following back but obviously many slip through the cracks. I also have a ton of people I follow who do not follow me so I can weed that out at little bit. Anyways click here to try Friend or follow .
I found this great site through Ten talents a great blog to find low entry giveaways and all kind of other tips and such for the blogging world.