Well, it may interest you to know that courts judging "emotional distress" is not some new Internet fad. In the year 1348 an innkeeper brought suit against a man who had been banging on his tavern door demanding wine. When the innkeeper stuck his head out the doorway to tell the man to stop, the man buried the hatchet he was carrying into the door by the innkeeper's head. The defendant argued that since there was no physical harm inflicted no assault had taken place, but the judged ruled against him [ de S et Ux. v. W de S (1348)]. Ever since then non-physical, non-financial harm has been considered both an essential element of a number of of crimes, a potential aggravating factor in others, and an element weighed in establishing civil damages.
This does *not*, however, mean that hurt feelings in themselves constitute a crime. It's a difficult and sometimes ambiguous area of the law, but the law doesn't have the luxury of addressing easy and clear-cut cases only.
As to why a new law is need now, when the infliction of emotional distress has been something the law has been working on for 667 years, I'd say that the power of technology to uncouple interactions from space and time has to be addressed. Hundreds of years ago if someone was obnoxious to you at your favorite coffeehouse, you could go at a different time or choose a different coffeehouse. Now someone intent on spoiling your interactions with other people doesn't have to coordinate physical location and schedule with you to be a persistent, practically inescapable nuisance.
Does this mean every interaction that hurts your feelings on the Internet is a crime? No, no more than everything that happens in your physical presence you take offense at is a crime.