I love open source software!
We use open source software for CMS, Blogs and Online-Shops.
When I do give lecturers/workshops I usually let students work with open source (and yes researching, finding appropriate forums is just a way to keep ahead and important to learn for to-become-webmasters - tricky thing to e.g. establish an accessbile, spider-able website in two languages via Joomla or Typo3 or ...).