After a bit of struggling, I finally finished my contribution to the german wikipedia article on regression analysis. It is not very easy nowadays to contribute to wikipedia. I learned a lot about copyright issues when I translated parts from the english wikipedia entry. Also it took some efforts to convince earlier contributors to accept my changes (well I hope I convinced them).
I learned also a lot about regression. It is definitely a large area of research now.
If you are fluent in German, take a look and improve the article. There is still a lot to do.