I think the difference is now people are selling big items for lots of cash (ie phones, prams etc) for £50. Hence when people get scammed or items go missing, large sums of money are lost. Because of this everyone is very wary (& rightly so) and accusations & mud slinging are rife.
Long ago (in a galaxy far far away) people used to use the For Sale boards to sell bits & bobs for £1, 50p etc so that if something did get lost in the post or someone didn't pay, you put it down to experience & shrugged your shoulders.
Now, there seems to be a lot more posters on there who just use For Sale & don't post anywhere else. I noticed it recently when I tried to sell a book (basically for P&P) & within an hour, it had 60+ threads above it caused by people starting multiple threads for the same pic trail, listing individual items on separate threads or bumping threads every 15 mins. That's what I get miffed about, regular MNetters trying to sell what once would be bought by someone fairly quickly, seem to have been usurped by people who just use the site for selling - sometimes using pic trails with loads & loads of items on or buying & selling prams like a used car lot.
I will climb off my soapbox now