"i'd rather sell a dog to someone on here than a random off the street iyswim?"
Both are as potentially dangerous. Unless you are willing and able to homecheck as thoroughly as a decent rescue, including asking to see mortgage documents or a tenancy agreement and then speaking to the landlord named on that agreement AND you are able to take that dog back at any time in the future if the new owner can't keep him you should NEVER rehome privately. By all means rehome FROM home, with a rescue doing a homecheck and offering back-up if it all goes wrong whether now or in 10 years time but that's as far as a private rehome should go.
Consider - how would a caring owner feel if the dog they rehomed to what they thought was a genuine family was in fact going to be used as a fighting dog, or bait for fighting dogs, or kept in a shed to be bred from year in, year out? Because it DOES happen.
What happens to the dog who is adopted by a nice family who in 2 years, 12 years or 2 months time can no longer keep him? YOU might have ensured he went to what you considered a loving home... THEY might take him to the vet or to the pound to be killed.
Could YOU take him back? I'd assume not as otherwise you wouldn't be seeking to rehome him. However, rescue CAN and a decent one WILL CONTRACT to doing just that. Rescue doesn't have to be kennels either, it may use foster homes. Getting a dog into rescue with no issues to iron out and time on your side is a feck site easier than getting him in there in X amount of years time when he is older, perhaps ill, perhaps now wary of kids or other dogs or men, and you want him out NOW. Rescue rarely has space that quickly and hence he would quite possibly end up on the streets or in a black bin liner.
Remember too that PEOPLE LIE! Some WILL tell you what you want to hear just to get rid of the dog fast. Let me introduce you to my beautiful dogs... they love children...
... you have only my word for that though, would you want to take the risk? Someone on here did recently. Within less than 48 hours her neighbour's infant child had been bitten and the dog was killed as a result.
These are the reasons why a private rehome is not a good idea and a website which allows such an advert, especially a parenting site, should be far more responsible and not allow them.