I'm guessing it stands for "street cred zero" as in having zero street credibility. Wiktionary defines "street cred" as: > Credibility among young, hip urban

I'm guessing it stands for "street cred zero" as in having zero street credibility. Wiktionary defines "street cred" as: > Credibility among young, hip urban dwellers; particularly important in the hip-hop and rap scenes. Google defines it somewhat more tersely as: > acceptability among young black urban residents Given that the user name says the user has no street cred, it's ironic that people would assume the user is "urban".