INCUMBENCY
The sites that currently are in the top rankings have the benefit of being the incumbents and it is a huge benefit. These incumbent sites gain hundreds of free links from scrapers.
Scrapers sites put up massive amounts of auto-generated content and wrap adsense around it. Where do these scraper sites get this content? They simply republish the serps for thousands of keywords. Thus the link and snippet for the top ranking sites gets republished on hundreds if not thousands of scraper sites.
I know what you are thinking, but Greg these scraper sites have very little link popularity. It is true that they only pass a little link popularity but a little link popularity from 500 or 1000 sites is some real nice link juice. And new sites do not have any of this link juice.
These scraper links seem to have the biggest impact on the second tier terms. The first tier terms have so much competition that the scraper sites importance is lessened. The third tier terms earn much less money so there are very few scraper sites.
Over time the barrier to enter the markerplace is rising. New sites used to be able to easily rank in days and then weeks. Now it takes months and it is not very easy if you do not know what you are doing. If you do have a new site don’t give up. Build as many pages of unique content as possible and attack the long tail of easy terms. Using these terms as a starting point you can slowly develop your site to take on the king of the hill for the top terms.
I have found a very similiar situation with the online directories, which pretty much do the same thing as the scrapers. My clients are in the medical field so the directories are just bought lists of doctors compiled into data directory lists with AdSense spread all over them.
It just complicates the seniority factor and the mass publication of a lot of data causes headaches when trying to do focused local SEO for dentists and orthodontists who are small one city shops. My client base is somewhere around 2000 and those directories get frustrating fast.
I love to encourage these small city service companies to link with other service companies in other citites. The links are very relevant and help users that are looking for doctors in other cities.