Pligg is a popular and totally free piece of software that can turn any domain or subfolder into a full-fledged social bookmarking site. Its been around for a while now, and you can find multiple examples of such a site by simply googling for “Powered by Pligg.”

Basically, users sign up and then they’ve got the ability to post links to content they find on the web and find interesting (or, commonly, content that they’ve written and want to promote ;)) From there, other users can vote on the link or leave a comment about it in hopes of triggering a discussion.

Although Pligg has been available for a while, the 1.0 release (and latest 1.0.2) represents the first time Pligg has been released under a “final” version as opposed to a beta version. Some hosts don’t allow users to install beta versions of software onto their servers – and many webmasters don’t want to run the risks associated with beta software either. Good news for the reluctant, because Pligg 1.0 is safe, stable, and will probably be around in this basic form for many years to come.

One loss is the old templates that were released for beta versions of Pligg – many of the visual designs were built around very specific software functions and operational codes that may have changed in the release version. Older templates and visual themes, therefor, aren’t compatible with the current software.

This does create a great opportunity for those of you web publishers who are handy with CSS and reverse-engineering code. New Pligg templates are in high demand, and it can be a quick and easy way to insert your link into the footer of dozens or hundreds of domains.

If you want to learn more about Pligg or download the latest version, be sure to check out their homepage at http://www.pligg.com/