I recently perused Marketplace, and it appears to be so thoroughly infested with barely disguised scams, bogus prices and other garbage as to be usable by only the most intrepid and determined shoppers.
My guess is that the default state is the scam garbage. It quickly learns your preferences. Which I hate. I miss having my 5 sections of craigslist I could browse over my morning coffee and not feel like I'm missing a deal.