FORBES - Oct 21 - The number of Americans using dating sites has tripled over the last five years, according to a new study from Pew Internet Project. 24% of Internet users search online for information about someone they’ve dated in the past, up from 11% in 2005. One in three social network users say they’ve sifted ex's profile. 29% Internet users had searched online for information about someone they were dating or were about to go out with, up from 13% in 2005. Similarly, 30% of social network users collect intel on romantic interests.