> Princeton University makes WordNet available to research and commercial users free of charge provided the terms of our license are followed, and proper reference is made to the project using an appropriate citation. [1]
Then I'd suggest you properly attribute them for the data, especially if you're going to charge people for access (in my opinion, IANAL). See their site on the matter:
You're right, of course. I turned the "about" page on. Was holding off until I could spruce it up a bit, but I guess it's ok for now. Wasn't expecting hackernews to really jump on this.