Powered by Direct Hit, Dmoz, and Inktomi in that order. They have had this mix for several months now, I don't think Hotbot will break their partnership, one of the co-founders of Inktomi helped create HotBot.
I am still wondering if HotBot made a change to DH as there exclusive SE supplier. There used to be the INK logo on the bottom of the search results page along with OD and they are both gone as of yesterday. Anyone heard if INK is out at HOTBOT?