“It’s complicated” could also describe the emotional calculations people in their late teens and early 20s make as they decide whether their relationships are “Facebook-worthy.”

For Stephanie Endicott and Marcus Smallegan, first year students at George Washington University, announcing to the world that they had found love in a college dorm was a no-brainer.

“Neither of us had been in a really good relationship before and ours turned really good really fast,” said Smallegan, who had posted a relationship on Facebook once before, only to have that girl move out of state and break up with him via a text message on his cell phone.

Some of their friends, however, have had less harmonious Facebook experiences. Both Endicott and Smallegan know of other college students who thought they were in a relationship — only to have it all blow up when they tried to link their two Facebook profiles as a couple.

Not all students post their relationship status. For some, it’s a matter of privacy. For others, it’s all about marketability. “I have NEVER changed my Facebook status — it has always been single, even when I started to get involved with girls. I think it’s better this way, until you are VERY serious,” a young man wrote in an e-mail.

But for many couples, being “Facebook-worthy” confers a status on a relationship. When a couple was “going steady” in the 1950s, the young man might have let his girlfriend wear his Varsity team sweater or given her his fraternity pin. But the 1960s swept aside those rituals. Now the Facebook link has become a publicly-recognised symbol of a reasonably serious intent short of being engaged or moving in together.

“For those in a relationship, the theme that kept echoing was that Facebook made it official,” said Nicole Ellison, an assistant professor of telecommunication and information studies at Michigan State University who has studied social networking sites. “That was the term they used. And when the relationship fell apart, when you broke up on Facebook, that’s when the breakup was official.” Facebook even produces a little red broken heart icon when a couple splits up.