"Those types of sites did not rise to the surface in our research, perhaps because they are new and not many are on them yet, or perhaps because people don't want to admit to using them," Smith says.
While hookup sites are becoming more common, 46 percent of online daters told Pew "finding someone for a long-term relationship or marriage" was a major reason they used dating sites, while 25 percent said a major reason they used online dating was "meeting people who just want to have fun without being in a serious relationship."
Chatting online or searching for dates on the Web "removes some of the pressure" of meeting people, says John Cacioppo, a professor of psychology at the University of Chicago.
"You come to some snap judgments when you meet face to face, and the Internet can make it easier to be yourself when you first meet someone," Cacioppo says.
Relationships are increasingly lived out on digital networks as people research a person's Web profiles before dating them, then they chat online, and later have a persistent connection with someone on Facebook even after a relationship ends. That trail of photos, timeline history and chat accessibility with exes has effectively ended the traditional idea of a breakup. The Pew study noted that 31 percent of social network users use websites to check up on someone they used to date.
Among social network users, 27 percent of people blocked someone who was flirting with them inappropriately, 22 percent of users blocked someone they used to date and 17 percent of people deleted social network photos of people they used to date, the Pew study shows.
To keep Facebook from placing a strain on relationships or scaring away potential partners people can "learn to edit themselves online," says Christie Hartman, an online dating coach and former behavioral scientist at the University of Colorado.
"You have to think about who you want to friend or defriend on Facebook, who you want to tag or untag on Facebook, because that information gets around in ways you might not realize," Hartman says.