As usual, when something gets popular, all the spammers invade. Twitter is no different.
I have not spent an incredible amount of time building my Twitter network, mostly because I am not convinced that Twitter has a real future. However, I am only following 318 people and already I have had to spend time culling the herd to eliminate the spammers.
It's amazing. In spite of the reality of permission marketing, it never ceases to amaze me how many marketers still spend their time shouting at the rain. It doesn't make sense to spam me with your marketing message when I can very easily just shut you off. If they spent time building value and establishing their credibility, it would make a huge difference.
Some idiots will never learn.