A cyber stalker is a sick and lonely coward individual who abuses the anonymity of the internet as his only possibility to molest another person. This kind of breed uses all kinds of internet services like talk forums or blogs for chasing his victims. The victims are mostly only accidental and get attacked for no given reason.
Commonly used accusations by cyber stalkers: 'XYZ is a nazi.' Or: 'she/he' (the victim) is known for having done this or that' (mostly sexual accusations or perversions). Or just: 'XYZ is a jerk because ...'