People who you only know through the internet or text messaging. People you've never met, and more than likely never will. This can also apply to those people who live their entire social lives through the computer. The term is short for virtual, due to the fact that these people are not real, only virtual.
Kyra: I have so many facebook friends, and some boys who like me! The boy's name is Josh and he lives in Texas.
Adam: Have you ever actually met, or have any proof that he's real?
Adam: He's just a virt, not a real person.
Kyra: Shut up, he loves me!