Thinking of looking up an old high-school sweetheart online? It may be more perilous than you realize:

It sounds innocent. You get to wondering whatever happened to that special someone you dated in high school or college, so you track her, or him, down online and send an e-mail.

Your old flame is thrilled to hear from you. You chat online, talk on the phone, meet for coffee. And faster than you ever imagined, everything gets out of hand and someone's marriage is ruined.

It happens a lot more often than you'd think.

"It starts with e-mails," says Nancy Kalish, a psychology professor at Cal State Sacramento who has studied the phenomenon. "It goes to IMs (instant messages), and the hotel room follows pretty soon afterward."

(Via Linkfilter.)