The online social networking has become a phenomenon in the last few years. People add friends and connect with old buddies all the time. You might accept people who request your friendship although you don’t know them.
What happens is that after being accepted by thousands of “friends” on Facebook or “followers” on Twitter, the scammers send a link that contains viruses or other dangerous software. Sometimes, the link that you receive appears to be a real Twitter or Facebook sign-in page, but it’s just a clone that requests for your password.
How to avoid: don’t add anybody before you check if they post something worthwhile on a regular basis or at least have some common friends.