Link Importance Taxonomy

I just met the very impressive Joe Laratro who we will probably hire for some inhouse SEO classes or PPC

We had an interesting discussion about what links count more than and he pointed me towards a presentation by Todd Malicoat . I thought it was great but pointed out that it wasn't complete or at least, it didn't address the type of questions that I had. I remember worrying alot about how to best harvest google juice and writing on link importance back in Jan 06 (and other times I'm sure)

I'll update my thoughts on link importance and I'd be honored if Joe uses this to refine his teaching in this area:

Image links vs text links. Text links are better although image links with alt text are better than just a banner. For the unitiated, many image links on sites are run thru a javascript adserver engine meaning that there is no followable link.

Single links on a page versus multiple. Each additional link divides the link power on the page accordingly. I'm still unclear on whether if Site A & B start with the same google power, which site's links are more powerful:
- Site A - has 5 outgoing links on one page, 4 pages with no links
- Site B - have 5 pages, each with one outgoing link

Relevancy: relevant is more important than irrelevant by a big ratio... Arguably, this is the most important.

Multiple links on a site - The 2nd link on a site is less valuable than the first. The second link to you on a page is less valuable than the first. The 3rd in both cases is even less important and so on. So, don't think a link on each of 20 pages is 20x better than a link from the site.

The Value of Links from Different sites - More important to Less Important (my list)

Best - Authority sites (including .edu, .gov, or any site that is at the top of the search engine for significant terms).

Original Unaffiliated Articles on blogs, websites, or forums that quote and link to your site (they probably count the same if they are set up right meaning that url, page name, keywords, and content are relevant and original. And that the content is substantative)

Original Unaffiliated Articles on blogs, websites, or forums that link to your site

Directories

Affiliated sites (either co-owned, co-hosted) - I'm not sure if google is yet looking to see if there are shared adsense, adwords, or webmaster management tools to determine affiliation and I'm surprised that more people don't ask this question.

Duplicate content - An article with links that shows up on two sites is of less value on the second site. And on the 3rd etc.

Worst - Reciprocal links - While some of this is OK, google will notice alot of it and will particulary dislike irrelevant links or links to spammy places.

PS - I think a fun project would be to quantify some of this...How heavy is the depreciation of the 2nd link to your site from the same page versus the 2nd link from the same site, different page...