One of my visitors was comming from http://ask.reference.com/ and it's not in the last SearchEngines.php i've downloaded yesterday.
Here is what a full search result URL look like :
It use the same parameter (q) but it's not reconized since the domain name is not in the list yet.
Attachment: ask.reference.com patch for SearchEngines.php
This also came up wrt referrer strings from answers.com.
Neither are pure search engines -- they're more like mashups.