If someone follows you on Twitter - should you follow them back?

Congratulations, you have a new follower on Twitter. 

Do NOT feel obligated to follow them back. According to Mashable’s “Complete Guide to Twitter Etiquette,” you are under no obligation to follow every person who follows you. In fact, following people blindly makes you look like a robot. Who you choose to follow on Twitter makes a powerful statement about your interests and your influence, so make every follow count. For your own sake, don't dilute your feed with tweets that don't interest you.

On the other hand, if that new follower is a real-life friend or colleague, it's considered a major snub if you don't follow back. The worst offense is the "Twitter one-night stand" — following others and then unfollowing them the minute they follow you back. It's an underhanded way to gain followers and it's just plain rude. And under no circumstances should you announce when you've decided to unfollow someone — or publicly shame someone for unfollowing you.