Hubpages  is a cool collection of user wisdom. I've contributed a couple of posts there rather than just add them here.

Got a ping from them a couple of days ago announcing a re-design of the site.

It's kept all the best bits of the interface for creating content (a very good Ajax driven interface that's just improved over time) and polished the interface and usability.

It's a pretty reliable resource as other users can comment and thumb up/down articles.

Unlike reference sites such as Wikipedia the range of topics covered here is pretty eclectic but growing every day - check it out!