Ask HN: Sending first e-mail to potential users from "waiting list"

Around 2 months ago I set up a "coming soon" placeholder page for one of my projects. It was pretty simple - js canvas animation, little bit of a description and a "leave us your e-mail" form. Just e-mail, nothing else.

I'm planning on sending out some invitations for beta-version of the website. I thought that a good idea might be sending personalised e-mails. It would be easy to write a small fb-spider that would gather names/locations of the people that are in the list from facebook to give me some insight. I could greet them with their name then (It conjugates in some languages) or write in their native tongue.

It's a detail really, but got me wondering - is it legal? How creepy receiving an e-mail like that would be?