The Bogus Accounts Problem @Twitter

I keep my twitter set to notify me of new followers, but I have those alert emails filtered & archived. I just took a look over the past two weeks, and the overwhelming majority (say, 70%) are bogus or SPAM accounts. That is crazy. I certainly don’t expect lots of real people to follow me, but that number of bogus accounts could be a harbinger of the challenges Twitter faces as it scale speed tries to keep up with the demands on the pipes it has created. I personally deal with this by blocking accounts & being selective about the folks that I follow, but I am abnormal in that sense. Other sites with social graph elements, like FB, LinkedIN, and upstarts like Plancast, Quora, and Namesake, have not been hijacked like this. Will the Twitter Police step in?