Paul Gibbons, 47, turned up at the family home of John Jones by tracing him from personal details he had placed online.
Gibbons travelled 70 miles to arrive with a pickaxe handle and accompanied by another man carrying a machete.
Mr Jones, 43, opened the door holding a knife for protection and there was a scuffle in which he was cut on the head, neck and hands before his partner called for help and Gibbons fled.
Gibbons, of Southwark, South London, pleaded guilty to unlawful wounding and was remanded in custody for sentencing.
A charge of attempted murder of Mr Jones at his home in Clacton, Essex, in December and four charges of online threats to kill other chatroom users were left to lie on file.
Gibbons said Jones spread rumours about him, the court heard, which led others in the chatroom Yahoo, Islam 10 to call him a paedophile.
Det Sgt Jean-Marc Bazzoni of Essex Police said later: "This was a terrifying ordeal for Mr Jones.
"His wife was in the bath, two of his children were playing outside and the baby was nearby.
"This case shows how careful you must be about protecting your identity."