Marc,
You might want to consider the way I've done it so far. The Red hyperlink on each term means anyone can simply click it whereby a new "page" is created and they can start writting. This may encourage ppl to write, but it may have some drawbacks (ppl creating useless empty pages or if something has been created and someone changes the reference that page is linked to eg the term on the glossary). Another way is not to have the "automatic" creation of pages by clicking the hyperlinks in red, instead anyone wants to contribute has to create the page manually.
When its blue it means someone has already created and written a page linked to it. Thats simple enough, well and good.
Then what about the look of it? bold might be easier on the eye, or the "definitions" style like the first 3 items which is bold as well as having the text on a different line and indented.
Everyone please fell free to give input.