Another released, but not yet documented, feature for is the `user_role` attribute. Specifically this can be used when testing the API and you need to ensure the response is ham. Setting `user_role=administrator` will guarentee ham.
Unless configured otherwise, Rakismet will default to being in test mode when the current `Rails.env` is `test` or `development`. Of course any explicit configuration via `Rakismet.test = true|false` will override this default.
This is a new (or at least undocumented) feature of Akismet that tells Akismet __not__ to learn from this request. This is useful for testing libraries or Akismet integrations. Per a discussion with Alex (an Akismet engineer), they will be blogging about this feature in the next couple of days, but it is already supported.