1.

Jack visits Meet Me and is shown Jill's profile. Jack likes Jill, so Jack clicks "Yes" to Jill.

2.

Jill logs into Hot or Not and sees that Jack is one of her new half-matches. She also likes Jack, so she clicks "Yes" to him and a double-match is made between them.

3.

Jack logs into Hot or Not and receives notification that he has a new double-match... it's Jill! Jack writes Jill, knowing she also clicked "Yes" to him.