I've been keeping a close eye on the different open source CMS's that are coming out these days, mainly for link building opportunities. If you're a Wordpress or Joomla theme designer you most likely have distributed free themes in order to build links and get exposure for your work. I'm aware that Google has been watching this practice closely because a lot of folks were selling the link spots(Sponsored Themes Discussed @ Webmaster World). Now if you're a web design company or freelancer, there is no problem using this as a form of marketing. Unfortunately the theme market for the likes of phpBB, vBulletin, Wordpress, Joomla, yaddy yadda, is way over saturated these days. There are all sorts of new open source CMS's coming on the market, and a handful of them are starting to get a large use rbase. There are CMS's for DIGG clones, forums, social networking sites, social bookmarking, web 2.0 and new blogging platforms. These are perfect times to grab some new business and get a chance to work with a different platform. Because there are so many the possibilities are endless, and would be a great way to expand your design firm to the next level. Lets take a look at 6 CMS's that are growing rapidly and are desperately in the need of both free and premium themes. Read 6 Untapped Resources For Theme Link Building
I agree with the OP, pligg is getting very popular and these sites seem to get PR very quickly. How about moodle for education sites? I thought that's also very popular. I have used plone earlier but others are new to me (thanks for sharing these). They might be good for designers but not for others sponsoring links.
Wow, there were actually some sites on here that I haven't used yet! Thanks! That's great considering every day someone posts about "this new link technique I found called blog commenting!"
I know what you mean..I made a posting about this in the suggestions section lol. This place has a lot of potential for good information and discussions but it is constantly bombarded with the same questions/posts all the time.