That is a complex terminology which I have found in the weighting of my Melayu.EU’s Post Mortem, where it dropped from PR5 to PR3. A HUGE DROP! Yikes!
Apparently, the internal links keep ….well to yourself. Even with a Do-follow, it actually causes more damage than ever, leaking your karma away.
One thing I do notice is that Domain Tools stated something about SEO SCORE:
Links
We factor in three types of links: On-domain links, Off-domain links, and No-Follow links. Each type of link is different and gives its own type of optimization to a pages it links to. We have derived our score to assume that the current domain wants to keep as much focused PR as possible so we mark down pages that link outbound more then a certain percent of the time.
On-Domain links: These help PR and generally boast a score because links are flowing back to the domain where the webpage is located and the pages inside the domain are likely to flow back to the original page.
Off-Domain links: They don’t hurt a page but they weaken the domain’s focusing PR power. We encourage people to link to good resources and it will not penalize a page if there are one or two links going off site. However if a page is 100% outbound links then at that point we drop the score a few points.
No-Follow links: We disregard these links and they are neutral. You can learn more about them by searching for “rel=nofollow” on your favorite search engine. We only want to see rel=nofollow links when third parties are adding the links. If you think the resource is quality then websites should not fear linking to it and giving them some PR. It actually shows search engines the site is a quality hub site. Another scenario for use would be if a link was to a third party and it was excessively used. This type of heavy linking to another site bleeds a site and we suggest it be sparingly use it in these cases.
I highlighted the part of OFF-DOMAIN LINKS. So I failed to score a 90% on most of the sites due to my paid post , and I found a tiny trick that my wife keeps on utilising, adding an internal link at all times in each post. That will boost the incoming links and lessen the outgoing leaks.
In essence, for every link you write, you place your OWN INTERNAL LINK at the same time,especially in relation to the post. Keyworded Links are important. A Joomla site will always score higher than a WordPress one due to the internal SEO Engines added with the Standford Whitepaper which PageRank is based on. I will have to research that more myself to engineer the pageranks.
Linkwise, SEO ENGINEERING 101 , the name of this site, scored 95% on the SEO Weighting with a 91% Meta Relevancy Links: 78 (Internal: 48, Outbound: 30)compared to the brother site which had a 90% SEO and 55% Meta Relevancy. (Links:141 (Internal: 74, Outbound: 67))
So , I should stop talking about rubbish and focus on the content itself.Like so, I will have to extradite my contents and split them up….yikes! More work..anyone willing to help??

actually, this whole PR thing is confusing. Tho everyone is talking about increasing links to increase PR, I have found that some does nothing (only one link to the site according to technorati), only has handful of vistors, fairly new blog and still get a PR 2 whereas some tried hard in exchanging links and still stay kosong. How to explain this huh… ?