The art of flirting with, hitting on, or seducing another person by means of the internet. It can be happen through instant messenger, email, facebook chat, myspace messages, and many other forms of text-based communication.
Often, it's risky business and requires extreme skill and intellectual prowess in order to be conducted effectively. The lack of emotion behind pure text can sometimes make it difficult to detect sarcasm or ones true intention behind what they are saying which can lead to extremely awkward situations (especially the following day when you see the other in person).
Jeff just spent two hours on facebook chat. He was cyber maccing on Debby.