I’d like to share this useful little information with you. It had been posted by Max (it’s in german) a few days ago. He describes how to get PageRank 1-3 back links for free and with a reasonable effort.
There are quite a few expired Wordpress subdomains out there that still have some PR because other websites still link to those former blogs. The only question would be: how to find those expired domains?
It’s easy: try to access a non-existing Wordpress blog like dfmwrqrsa.wordpress.com. At the bottom of the page you’ll see the following message:

The blog you were looking for, dfmwrqrsa.wordpress.com doesn’t exist but you can create it now!

Now go to Google and just type in: “The blog you were looking for,” “doesn’t exist but you can create it now!” Google will find you all those expired blogs that still have back links or did have back links before. If they didn’t have back links Google wouldn’t be able to find them. Now just check the blogs back links to see if it’s worth registering it with a back link check tool.

To save you some time: it’s not worth looking now as Max, me and some other people already registered the most juicy blogs. However there will be more soon (Wordpress blogs expire all the time). Therefore it’s definitely worth to have a look every now and then.

Btw, the same principle works with .tk domains.

This is what you have to give Google: site:.tk “This domain is still available”