Do You Know Your Twitter Karma?

Have your checked your Twitter Karma?

Twitter Karma is one way to check out who is following you on Twitter and who is NOT following you on Twitter. It is a completely FREE service and you can check as often as you would like. I try to check weekly or bi-weekly. Especially in the beginning - if you follow too many you cannot follow anymore; so why waste following someone if they are not conversing or following you back?
Reasons to follow someone:

They are in your niche

They respond if you re-tweet or converse with them

They are following you

You really know them

They post great tweets

Reasons not to follow someone:

They never converse with you

They have no activity in weeks or months

They are not in your niche or interesting to you

They spam you

They only tweet about themselves

What are your reasons FOR following someone on Twitter?