"Catfishing" describes con schemes that involve the mark developing a trusting (usually romantic) relationship with a fictional person.
In the most common form, the conman finds a guy on a dating site, and pretends to be a girl who is interested. The relationship escalates for a few months, including swapping risque photos, until they try to meet in person (the fictional identity is always several states away). The conman than uses the pretense of logistical barriers and bad luck to extort cash from the mark, while delaying the in-person meeting ('my connecting flight through Detroit canceled, and I don't have money for a hotel! please wire me two hundred dollars ;_;'). The mark gets increasingly distraught and desperate, and is too emotionally involved to realize he is being lied to.
The Te’o case, as you mention, doesn’t follow the outline above, because to many, there is the definite possibility that Te’o was in a homosexual relationship with the person involved (that claimed to have hoaxed him), and that this spin was much more damage control for Te’o (given that the NFL does not have an ‘out’ gay player).
In the most common form, the conman finds a guy on a dating site, and pretends to be a girl who is interested. The relationship escalates for a few months, including swapping risque photos, until they try to meet in person (the fictional identity is always several states away). The conman than uses the pretense of logistical barriers and bad luck to extort cash from the mark, while delaying the in-person meeting ('my connecting flight through Detroit canceled, and I don't have money for a hotel! please wire me two hundred dollars ;_;'). The mark gets increasingly distraught and desperate, and is too emotionally involved to realize he is being lied to.
Probably the most famous catfishing case in the last year was college football player Manti Te`o's fictional dead girlfriend (which does not completely follow the textbook outline above): http://deadspin.com/manti-teos-dead-girlfriend-the-most-hear...