> 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]

Interesting! I never realized this.

1. http://wordnet.princeton.edu/wordnet/download/

That's nearly the BSD license. Though if I recall, some of the data files have unique licenses.

For now, that's the source of most data. I'll be adding more as time goes on. First up is pronunciation.

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:

http://wordnet.princeton.edu/wordnet/citing-wordnet/

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.

On their site it says: "Due to funding and staffing issues, we are no longer able to accept comment and suggestions."

What if you give a % of your revenue to them to help them, in return you could be the recommended API on their site?

aren't we supposed to cite the use of WordNet?