Couple of months ago Google changed part of their nofollow strategy.
What they changed was the way they calculated page rank distribution to outgoing links.
However the main goal of nofollow was to let Google know that a link out of a blog was not to be considered as relevant and should not be counted as such.
The ‘potential’ problem with outgoing links to irrelevant sites is that our blog will be regarded as less focused, it would be a case of Theme Bleeding (*1). The theme loosing relevancy.
With Google’s change of the PR allocation many SEO experts suggested to abandon nofollow altogether, however I think this would cause the undesired effect above.
Still, there is be a better way to resolve the problem of Theme Bleeding (*1). And it would also be effective for any other searchengine that obey the rules in the robots.txt file.
The robots.txt file is a set of rules that tells the search engines what they can index of your site and what they can not.
With robots.txt we can instruct the search engines to skip directories, and that is what we can use for our improved nofollow strategy.
Normally when you write a blogpost and enter a link like <a href = ” http: / / somewhere.com “> the searchengine will follow the link.
To prevent this from happening we will change our link to
<a href = ” redirect/redirect.php?redirect=http : / / somewhere.com “>
The content of redirect.php would be
<?php
header(”location : $GET['redirect']“);
?>
and the contents of our robot.txt would be
User-agent: *
Disallow: /r/
You have now implemented a nofollow strategy that works for all search engines. An open question is does Google assign outgoing page rank different when you use robots.txt rather than when there are no rules in robots.txt. I have no idea. I guess it must be tested.
One benefit of the process could be that you are now cloaking your links to affiliate sites, though the fact that the destination url is in the redirect url, may be enough to give away the game.
And trouble with the whole process is that we need to remember to put in our link in the redirect form rather than in the normal form.
If you are using Wordpress as your blogging platform and have a lot of existing posts, with affiliate links, then this process can become very boring.
And since I have a few of these blogs, I wrote a wordpress plugin to do the process automatically.
My requirements to the plugin are:
* Automatically change all external links in the blog to redirected ones
* Cloak the links in the process, so the redirection destination is not shown.
* Make it possible to exclude selected links (to pass outgoing PR to sites of choice)
* Reorganize the internal linking in the blog so all postings in one category are linked together. Increase Theme Density (*1)
* send an email with weekly and monthly click through stats in CSV format, so it can be imported into excell.
I have installed version 1 of my plugin on several of my blogs and will test over the next period how the ranking is improved in the search engines.
Does this have your interest?
I plan to package the plugin up and sell it eventually.
However, to do this I will need time to test it on different blogs, with different themes and layouts.
Unfortunately that takes time 
but I shall let you know when it is ready.
If you want to know when the plugin will be up for sale enter your name and email below, and I shall let you know.