For those of you who may have missed the tweet, the wiki community (wikitechs? wikiteam? wikites?... skritt?) have been adding more places for you to use your API-keys on the wiki.
For a complete list of pages using API-keys, including those that are still a work-in-progress, you can head to this category page.
To create an API-key for your account, go to ArenaNet's website and sign in. For more information about the keys, please see this overview. Note that using your API-keys on the wiki will store the keys locally on your computer. Your keys and account information cannot be seen by any wiki user, and you can remove them from your computer by clicking "Forget stored key" on the respective wiki pages where you have used them.