Still curious as to why DMOZ has never gone after the paid listing market. Yahoo does well with it, Why cant DMOZ? They could charge $300 easy for a listing and a lot of people would pay.
If you are a "senior" editor with thousands of listings, it can get very expensive no matter what listing price is.
There is a promise on the DMOZ charter that it will always be free to submit to to be listed in. The fact that DMOZ is different to Yahoo means there is room for both to operate according to different models. DMOZ does not exist for webmasters and provides no services to them, they are only interested in surfers and their interests.
The thing with open source is that the whole model changes if you start paying editors. Editors do what they do based on what interests them and because they are actually devoted to bringing good information and collecting good links. This is fundamentally different from the business model.