I have noticed the exact same thing! Sites with 0 backlinks, no PR are ranking #1 for medium difficulty keywords. And just like others have said, amazon, web 2.0's, really new sites, youtube are ranking really high. Maybe time to start not doing any backlinks
you are aware that amazon, web 2.0s, youtube and wikipedia are the MOST BACKLINKED sites on the web right?
and amazon has some of the dirtiest 2nd hand backlinks around
think, you spam comments @ articles, web 2.0s and at wikis that then link to your site right?
everyone does
if google started really hitting spammy links, you'd see articles sink first, then wikis and then web 2.0s
(based on % of natural nonspam backlinks)
if they instead hit the sites that have no outbound links that are targets of spammy links, you'd see what we are seeing today
that being said, if amazon crashes in serps then you know spam doesn't work anymore
(one amazon mns tends to have over 100+ links to different amazon pages, and is usually powered by a multi tiered ranking campaign, so the net effect would make amazon's head first on the block)