Are these sites in the SERP really weak?

Well if you want to do serious backlink analysis, Yahoo Site Explorer is a good start. Unfortunately, there is no perfect backlink analysis tool. Google's link: operator is useless and can safely be ignored.

Remember, it's not about the "number of backlinks." a lot of backlinks are just noise. In some cases, even a single great link can drive all or most of a website's rankings.

Here is how you might use YSE to find a site's best backlinks:

1. Install some free plugin that shows SEO data on search results. I use SEOquake in Firefox (good and free), but there are others.

2. The plugin should normally be turned off, so as not to drive the search enginges crazy.

3. Go to YSE and run the link analysis query (filter out internal links -- that's the "except from this domain" setting, and set it to return links to all the pages of the website, not just the home page).

4. Turn on the pligin and refresh the page.

5. Sort the results in descending order of PR.

6. Turn off the plugin: you don't want Yahoo to start denying you service because you are sending automatic queries.

7. Links from pages with the highest PR will be at the top.

8. Some plugins show you which links are nofollow and some don't. One way or another, you need to ignore the links that are nofollow.

9. In general, the dofollow links with the highest PR are the site's best links (though in reality it can be much more complicated than this).

The problem with YSE is that it is expected to be dropped by Yahoo within a year.

The link analysis tool of the new generation will be the SEOmoz Open Site Explorer, which is brand new but will eventually become much more powerful (and it is pretty great already). The paid version of OSE lets you browse 10,000 links, and the free one only 1,000 (same as YSE). OSE does its own spidering of the Web but it hasn't found as many links as Yahoo yet, and it gets updated much less frequently (1ce a month, I think). But never mind that, I am sure SEOmoz will work it up into the tool of the future. Unlike YSE, OSE shows link anchor text and lets you filter out nofollow links -- a very helpful feature.

I hope this helps!

Different markets equals different algo calculations - from my observations.

Credit repair has some sort of filter to keep, let's say, 7 "company" sites out of 10.

Lower importance keywords can be inside another "package" with different calculations, let's say 3 "company" sites out of 10.

Sometimes these sites do not have high number of backlinks, or high authority backlinks, STILL they manage to keep top rankings - which then brings them backlinks and/or authority cause people start creating articles about them, backlinking them, etc etc.

In fact this is a smart and natural move from Google to avoid a domination of top 10 by clever SEO's.

Just my 2 cents from daily observations since 2004.

Extremely hard, especially if they're old and exact match domain.