Right, if you are going to be sending email out for notifications of future products then you should probably set that up as a separate option and make it double opt-in. That's what most services do. In other words, they have the sign-up and then there is a checkbox or something similar which says something to the effect of "notify me of future blah blah blah." If you don't check that box then your email is typically only used for things like resetting your password.