Facebro
A fake brother who you added on Facebook because he asked you for a sibling and you said yes.
'Bro, I want to be your brother on Facebook. Can I be your brother? Please?'
'You're my Facebook brother now. I'll beat you up if you don't like me.'
'We're brothers now. I'm gonna post your face on my wall and call you 'Brother Facebro'.'