Recently, I see many updates in my Twitter timeline containing updates about that so called “get more free followers”. The idea is to encourage you to join a service that will boost your number of followers. Sounds familiar? A simple question: what does those number mean (for me)? What do I want to prove by having hundreds or thousand followers? Nothing.

If you try to find service like this, you will find many. They share some common characteristics:

• Ask you to login to their websites, it means you give your Twitter username and password.
• Sometime, they ask you to follow more people and give you new followers.
• And then… the worst part is that they will send updates from your account.

If you’re aware that there’s something wrong with this practice, you can stop doing this. But, if you don’t check Twitter regularly, don’t be surprised if you flood your timeline with those rubbish. Also, you will flood people with useless updates, too. This happens usually because you don’t know when and how those services updates your account. Remember, you gave them permission to access your account when you started using them.
Few weeks ago, I saw one one people I follow used a service like this. His account sent updates few times a day. Not sure about the frequency, but he had more than ten updates promoting the service. And, it seemed that he did not login to his account during that time. What happened next? He got his Twitter account suspended. OK, probably I had a wrong conclusion, but I couldn’t find any other reasons about the suspension.
Personally, I always spend few minutes reading about the service using Twitter login mechanism. I try to get some basic information, e.g:

• Login method — Twitter already has a standard secure recommendation. Your login information will not be stored to services’ server.
• Privacy statement — Even they don’t have lengthy paragraph about this, but you should read and understand it.
• Read more about the service. How the services deal with your login? What will they do with it?
• Last but not least — well, it’s my personal preference — do you really need the service?

UPDATE (added later):
Here are some websites that you provide what so called “get more followers” AND you’d better be careful!
tweeterfollow.com and tweeteradder.com — Both are using the same rules. They will ask you to follow other users first, and will give you new followers as “reward”. Here’s what a user experienced:

tweeterfollow.com was sending messages from my username, so I closed my account with them and then changed my Twitter password. Now I’m locked out of Twitter…it tells me I am trying to login too many times with the wrong password. I assume this is because tweeterfollow is still trying to tweet on my account?! Ugh!! (story source)

There is another story about tweeteradder.com, and from Twitter’s Get Satisfaction forum.
There are another services here twitter-train.com and twittertrain.info, but their websites are suspended by the hosting provider already.