CNN covers Facebook’s facilitation of emotional affairs and infidelity.
Ian Kerner writes (excerpt):
[W]hile feeling attraction is unavoidable, acting on it crosses the line. Attraction is one ingredient of an emotional affair. In order for attraction to launch into an emotional affair, a person has to also develop intimacy and, eventually, a feeling of connection with that person that supersedes their current relationship. In other words, attraction + effort + intimacy = emotional infidelity. Take away one, and all you’re left with is a natural instinct or a harmless Facebook friendship. Put all three together, and with friends like that… your relationship has a new enemy.