For those of you unfamiliar with the purpose of forums, forums are gathering grounds for different discussion topics in the form of threads.
There's all kinds of discussions, from absolute beginner talk all the way to technical bits, like programming and running ISOs. And there's always a community cafe, which breezes through material unrelated to Ubuntu.
The community is very active and vibrant, a strong reason why many people love Ubuntu.
Still interested? Learn about where and how you can contribute to Ubuntu.