>>4, I remember a website like that a few years ago. It was a 'viral' thing: You'd enter the email addresses of people you had a crush on. The site would then email those people, telling them that someone had a crush on them. They'd be invited to come to the site and enter their crushes. And so on.

The thing is, it never worked the way it was supposed to. People wanted to know who had crushes on them, so they'd enter a lot of names - people theywere really interested in, people they were sort of interested in, people they thought might be interested in them, etc. The site encouraged this as it helped bring in more people. However, it ended up meaning that when people were notified of a 'mutual crush', it didn't necessarily mean either party was all that interested.

Ultimately, there's no risk-free way of finding love. At some point you'll be vulnerable.