Cyber stalking/annoyance unlawful?

From this link.

A good law? I dont know everything about this, but on the face I just dont get this. The internet is not a US owned property, how do you enforce something like this in a world wide web? Besides which, since when are you not allowed to be anon on the web? Isnt that the whole point?

I really just want to know what intrest group pushed for this? What exactly are we trying to get to here? Are we protecting somebody with this law?