daleh, the criteria I first used for the online wwftd dictionary was verifying a word in two qualified sources; and by qualified I mean something found on my bricks and boards reference bookshelf, or the online equivalent thereof (e.g., OneLook, World Wide Words, Merriam-Webster Unabr. online, OED2 online, etc.).

I have expanded this criteria only slightly to include words found in online usage via Google News or Google Books.

Exceptions to the above are per Editor's Whim.