A woman (or a man) who is sexually promiscuous by flirting and role-playing sexual situations with many strangers (or near strangers) online over the internet.
A girl who you talk to on the internet, and sometimes send pictures of your erect penis. Frequently someone you cybered with and then got to know better. Sometimes they can become good friends.. other times they just clog up your inbox with junky forwards. Or turn out to be guys.
A girl who flirt's with and/or has sex with many internet men.
I guess it is really any girl who meets guys on the net.
"Hey dude, I think your girl is an 'internet slut', she waz jus' coming onto me on IM. So I disconnected and came straight over to tell you to ditch the bitch."
"I'm meeting up with this 'internet slut' for sum casual action."