When you Linz someone you're basically saying 'Yeah, okay cool'. In a sarcastic manner as if to say you didn't give a shit as to what that person had just said, and you weren't really listening and/or you don't care.
Closely followed by then ignoring that person and if on MSN blocking that person.
Person 1:'I dunno what to do, she's amazing, I'm crazy about her, I think I'm in love with her man...'
Person 2: Yeah, Linz.