There was a website that did this around 2002 and it was funny because I'm pretty sure their technique for getting new users was to send false positive spam mes

There was a website that did this around 2002 and it was funny because I'm pretty sure their technique for getting new users was to send false positive spam messages, "Someone has a crush on you. Come to find out who." Really nobody did, but you inevitably went to the site and entered the email of every person that you had a crush on in the off chance it was real. Then, BAM email database expanded rapidly. This idea is super viral.