A free service from Thespark.com. You enter your email address, and that of a girl (or guy) you like. The person(s) specified get(s) an Email from the pimpin' cupid that says something to the effect of, "Someone likes you. Go here." When they do go there, they fill in a list of everyone that they like. If your name is on the list, you are both notified. It's kind of like how things in ninth grade were, when a random girl would come up to you and say:
Hey Evan, you know Jane? She wants to know if you like her but don't worry if you don't I won't tell her you don't but if you do then you can go out sometime 'cause she kinda likes you and she just broke up with Nick blablabla.
Except it's a lot less annoying