What's a shadow profile? Sounds so sinister. It's probably just a line in a database with your email address and phone number. It's not like Facebook is actively keeping tabs on people that don't have accounts.
So, I wouldn't think it a far leap that Facebook might correlate non-member invitee e-mail addresses with, say, the activities/interests of the inviter. This could be happening right now for all we know, or it could happen in the future. Once they have the data, it's their choice.