Are pligg sites any good for backlinks? Are they dofollow? I found somewhere a list with a few hundred pligg sites and I became interested.
Some are dofollow and some are nofollow. I've found the story links are nofollow but comment links dofollow, weird. They are fine for backlinks, try to keep on target with your site.
I think almost all Pligg sites are now nofollow unless they never updated from the old version but in that case they are probably already full of spam.
DoFollow or NoFollow really doesn't matter that much if the Pligg site is relatively popular. Look at DesignFloat: do you think it matters if your links are DF or NF once you hit the front page? You'll be getting instant traffic from visitors legitimately interested in your content, which builds up your reader-base. Plus, Google will count NoFollow links, just not as much as DoFollow.
This is what I'd do: 1. Find several pligg-powered website lists and combine them removing dupes in the process. Or alternatively build your own by scraping Google SERPs for a number of pligg-related dorks. 2. Remove dead sites. 3. Sort by Alexa traffic rank (popularity) and check PR for the top 50-100 or so. 4. Use the list of top 50-100 sites to build quality backlinks. 5. Enjoy the results PS. You might want to code some php scripts for the above tasks. Doing them manually would take too much time.