To Refollow Or Not To Refollow?

Twitter Etiquette.

To refollow or not to refollow that is the question? Do you refollow everyone that follows you?

For me when I get new followers I go to each one of theirs' Twitter page, read their bio, check out their sites, and read their recent tweets. if I find that I have something in common with them then I refollow them. Regardless of whether or not I refollow my followers I send a direct message to all thankingthem for following me. I'm in no way saying anything bad about those I do not refollow just that I do not see a connection with them. Most of my followers I do refollow. Mind you I do not have tons of followers I only have a few. So My question to the twitters that have hugh followings iswhat is your rule of thumb when it comes to refollowing your followers?