While I don't condone illegal activities, we're all guilty of them at some point, (I like looking at it through the "it's only illegal if you get caught" mindset) but then you could look at it as a canceling out method: she's harassing you and such, and you want to end it, so you put the tapes up online/mail them in/make money, and everything (assuming there's nothing else to come of this later on) is all said and done.

At least, that's how I'm looking at it.

Still though, blackmailing this woman? I would just ignore her, and be safe. Sure, you may not make any money putting the tapes up anywhere, but then again you're definitely not loosing money in case police/lawsuits come your way.