Blogs, wikis, social networks, social news aggregator. Although there’s certainly been a lot of hype around these things, when applied in the right circumstances they can serve a utility for many people and businesses.

Fortunately, it doesn’t cost an arm and a leg to get started building out your own Web 2.0 toolkit because there are free, open-source Web 2.0 applications that enable you to operate your own Web 2.0 services – for fun or for business.

Here are 5 of them:

  • Chyrp
    is a lightweight open source blogging application modeled after Tumblr.

  • Elgg
    is a social networking platform. Although I haven’t yet tried it out, it looks very promising and it just had its 1.0 release.

  • MediaWiki
    is the wiki software that was originally developed for Wikipedia.

  • Pligg
    is the most popular Digg clone. It runs on PHP and MySQL.

  • WordPress
    is one of the world’s most popular blog publishing platforms and some of the most trafficked blogs on the internet run on it.