Ask HN: Do websites really sell for ~1 P/E?

I stumbled on to this website: http://www.websitebroker.com/ where people put sites up to buy and sell. Looking at the listings, I find some sites selling for $280, with $26 per month current profits. Another lists for $780 with $160 current profits, etc, etc. You'll make back the price in less than a year for most of those sites...

I feel tempted to buy one of those cheap ones and just collect passive income for a year. But then... why are they selling? Or is it all an illusion and everyone is trying to rip everyone off?