Stalked by Twitter

I am not a regular Twitter user, and I have now found the process of follower association annoying. Today and not for the first time, I have received email notification that I have so and so following my Twitter. This person (supposedly), who is following me, tends to have few hundred followings, but followed only by one or two people. We do know, through inference, that these people are either selling products or of ‘themselves’. However, the issue I have with Twitter is that; I am and get followed by these people without my permission to do so. This is different from say, Facebook, which asks me if I want to be associated with so-and-so person, that I have to accept the invite. Now, Twitter works in a different way, each time I receive the notification of a new follower, I have to log in to my Twitter account so that I can remove the person from my follower list and block them. I do not wish to see my Twitter profile filled with such people who have profile images, featuring a ‘suggestive pose’. When it first happened I felt quite violated and still do. I consider my online profile to be in a minutiae way, a representation of myself and wish to regard my online space to be self-governed. Should I not have a say in who can and cannot follow me? Should I not have control over my online space?