> How many users "MITM" their own SSL connections?

If you're looking for a startup idea, this is one: to check that what the manual says about outgoing data is true, and to what degree they compromise privacy. Decorate with 1-5 stars ratings. The ultimate goal is to have companies pay you to test their products.

However right now not enough people care about this, but it might change quickly. So starting it now might be a coin flip.