Yes. All forms of nicotine are unhealthy. Teens should be extra careful about exposing themselves to dangerous and addictive substances. Ecigarettes don't have the tar and carcinogens that regular cigarettes have, but the dangers of nicotine are still present.
In some ways. Electronic cigarettes are devices that provide flavored mist and a nicotine content similar to that of a cigarette. They don't contain tar and a lot of the other toxins contained in cigarettes, and they don't release second hand smoke for others to breath. They have plenty of nicotine though, and are therefore addictive. As a rule, drugs that cause addiction are bad for all people, young & old.