The clash ended with Paul Dudfield needing 25 stitches and permanently scarred after losing part of the cartilage when his ear was bitten by 35-year-old Robert Moore, Wolverhampton Crown Court heard.
The pair had been involved in an angry exchange on the internet over a former girlfriend of the latter, revealed Mr Edward Soulsby, prosecuting.
A text message from Moore offering to meet for a fight was ignored but they did bump into each other by accident as Mr Dudfield - whose family lived on the same Wednesbury estate as the other man - was walking home from work on October 2.
The victim's father and brother went looking for the attacker after the incident and were involved in a confrontation outside his house during which Moore was armed with a wallpaper scraper and his brother-in-law Jason Burke, 29, picked up a piece of paving slab.
Mr Soulsby explained: "There was a scuffle during which the victim's ear was bitten and the wound needed 25 stitches. His father and brother heard what had happened and went looking for the attacker.
"When they found him he threatened them warning: 'I know where you live. I will bust your windows and set fire to the place.' He was armed with a wallpaper scraper and they decided to leave. His brother-in-law chased after them with a piece of paving slab."
Moore from Devon Road, Wednesbury admitted wounding on the basis that he had not intended to cause such a severe injury. He insisted: "There had been bad blood over the Facebook postings but we met by chance. He had me in a bear hug and I bit him."
The victim said in a statement: "I try not to look in the mirror any more. My pride has also suffered."
Burke from Beaconview Road, Smethwick pleaded guilty to affray on the basis that he went to the aid of his brother-in-law after seeing him confronted by two other men outside his house and picked up a piece of paving slab to protect himself while chasing them away. He was given a six month jail term suspended under supervision for 12 months.
Moore was sent to prison for two and a half years by Recorder Abigail Nixon who told him: "The bad feeling between you and the complainant did not give you an excuse for what happened later."