Great changes!

I can not see any reason that anybody but the seller be able to post in the their for sale post.

Is it really necessary to tell somebody 'nice sign'
Or any other comment?

Think about it, how many for sale post get hijacked and before you know it a sign for sale turns into aunt sally's sick dog!

Own something, post a pic, with price
If somebody wants to buy it, they contact you by email,phone, or pm
If somebody has a question, they contact you, if you feel YOU need to update your ad, then do it

Where else do you ever post anything for sale and people get to post all kinds of comments?

Its for sale---if you dont like it or the price then dont contact seller
SIMPLE!!!!

Yes its against the rules to post non-pertinent or derogatory comments, BUT IT HAPPENS ON ALMOST EVERY POST

It would eliminate alot if petty bickering and save mods alot of time