Actually a great idea! Wikipedia articles do very well in search engines and could drum up some interest in ham radio in general and DXing specifically.
I warn you, though. Doing articles for Wikipedia is very work intensive. Their creation and editing process is very strict and unforgiving, and very, very arcane in many ways. It would be best if someone familiar with their requirements volunteered to take your material and convert it to their editorial process. At my previous company, we hired people to write and post our Wikipedia entries so they would fit the site's requirements.
If you haven't checked to see if there are already entries on DXing, that should be your first step, of course. If there aren't any, have at it! Or you may want to link off existing material on ham radio on there already.
(Author of the new book RIDING THE SHORTWAVES:
EXPLORING THE MAGIC OF AMATEUR RADIO)