Now that there's software that will automatically follow people on twitter if they tweet certain keywords (and then unfollow them a few days later if they don't follow back), spammers on twitter are heating up.
As an experiment, I posted a tweet that had the phrases "make money online" and "internet marketing". Within 6 minutes I had 5 new followers.*
I'm starting to wonder if Twitter is going to find away to prevent this. Perhaps everytime you follow someone you're going to have to type in the characters from one of those images, like this one:
Getting a lot of people listening to your tweets and sending a small percentage of them to whatever links you post is just too good for people to pass up these days.
* Now 6 followers in 8 minutes