I've been a contributor since January, 2006. An look at my contributions reveals that my expertise seems to be within the pop-culture realm: film, sci-fi, cult phenomena, etc...e.g. material related to HHGG, MST3K, et al. It's especially exciting to try looking up something in Wikipedia and discover that it hasn't been added yet. That's your opportunity to make a significant contribution. E.g. when I looked for a description of the Haggunenons under "Races and species in The Hitchhiker's Guide to the Galaxy."
I'm still new at this and I know I'm making mistakes (and I should probably do more RTFM) but most learning experiences involve making a few mistakes. I hope it isn't too much trouble to fix mine.
thanks to: JohnDBuell for help with Haggunenons