If the answer is "NO", you must ruthlessly unfollow or block them.
I follow around 2,000 people or less on my Twitter twitter.com/iwebu. The less comes in when I periodically decide to purge followers who are:
- Inappropriate - "Have you ever wonder what is the best way to make a woman orgasm?"
- Tweeting in foreign languages I don't know - "Deutschland wird Weltmeister , Nur Italien nicht! "
- Clearly spam - "Ready to make some pocket change right now? "
- Obscure - "Behold the turtle. He only makes progress when he sticks his neck out."
- Completely irrelevant - "Golf coaches, what's best way to teach/support a young (6yo) golfer who is said to be "excellent" (by someone other than his mom)."
- Irrelevant - " I originally made them with ground flax seeds... felt less guilty but they didn't feel authentic"
- Inappropriate - "Just go to www.teenkontakt.adultcrowd.com and meet horny teens"
- Clearly spam - "I found this great website for getting a six pack for the summer"
- Tweeting in foreign languages I don't know - "Смотреть порно онлайн Лесбиянки на лужайке похоти"
- Obscure - "Wild yam has many effective uses"