I don't think the problem you are noting (about others not wanting to do the same) is the one being discussed here, though.

I think you are saying, I don't want to give you my address book and have it go pester people with this service ("I joined NeatoBlog, come join to!!"); whereas, I think the thing being discussed here is, offer up address book and allow a page to populate from that which says, you gave us bob@mail.com, and we have an account here--bobbobbob--using the email address bob@mail.com. Do you want to circle/subscribe/whatever bobbobbob? Which is different from it saying, we don't have a bob@mail.com--let's email bob and ask if bob would like to create and account! (ew.)