Reviewing the SEO Experiment

I've not looked at the results of the target="_blank" experiment for a while (3 months actually), so first a recap.

Basically, I was wondering if using target="_blank" in links hinders sites as far as SEO and PR are concerned, so I set up 3 test blogs last October. The first didn't get any links in; the second had links in and the third was linked to from the same pages as the second, but using target="_blank" in the link.

Now this experiment isn't perfect. I'm using an equal mixture of my own writings and articles across all three blogs, posting to each at the same time. But there are other sites that pick up these articles and publish them as well from my blogs, and I'm not controlling how those links look. But overall, it should give a general impression of what's going on. So here's the current state of play...

Site 1 - 33 posts - no links.
15 pages on Google, all grey barred.

Site 2 - 34 posts - 'good' links.
40 pages on Google

PR 3
October - hello-from-austria-going-back-to-my.html
October - costa-rica-beaches-most-beautiful.html
October - things-to-do-in-boulder-colorado.html
November - multi-leg-flights-explained.html
December - know-your-bag.html
January - reinvent-your-sports-spirit-with.html
January - timeshare-travel-discounts-travel.html
February - self-catering-accommodation-in-style.html
2008_01_01_archive.html

Site 3 - 34 posts - target="_blank" links.
38 pages on Google

PR 3
October - 10-reasons-to-visit-berlin-germany.html
October - traveling-with-children-in-ireland.html
October - hello-from-austria-hiking-through.html
December - ways-to-mark-your-luggage-for-easy.html
February - sunny-outlook-for-spains-sunshine-coast.html
February - how-to-research-and-book-cruise.html

There are slightly more pages page ranked on (2) than (3) - but not enough to get excited about! What is interesting is that it is internal pages that are ranked - not the home page. And they are either PR3 or nothing. What is interesting is that the page ranked pages have changed since the last review, so I'm guessing this is more to do with an external factor. Having said that, the first site, without any links in, doesn't have any page ranked pages and hasn't got all of its posts cached. Thus showing the importance of link building.