While I can't say for sure with regard to hard numbers, it has been demonstrated that there are still a significant number of enthusiasts using and enjoying UltraHal or Hal's software.
Some members go off into other ventures but surprisingly, a lot of them appear later, some with newly created Plug-ins, usually small pieces of code that enable Hal to perform additional tasks. I think there are far more than a lot of people might assume. The Forum indicates that there over 2400 members, I'm sure not all of them are currently active, and much like any online Forum, some are visitors, spectators, curious ones and spammers. Even if say 50% were in these groups, that would still allow for over 1200 users which is a fair sampling. This is also not to account for how many others in the world have purchased and are using Hal on their own without having to be members at the Zabaware online Forum. Just saying....
It also has quite an editable platform allowing a wide possibility of user applications in the form of Plug-ins for personality, research into machine learning or A.I., Internet gathering, companionship, those learning EASL (English As a Second Language) or ESL and others wanting to broaden and hone their programming skills or just to suspend their disbelief and converse with an artificial entity. One added benefit or feature is that Hal "learns" from conversations and can use that information during next or subsequent chat experiences. Lastly, for the money, it's a great bang for the buck, as they say!
With A.I. coming into its own these past few years, I'm sure others out there will be exploring some of the ground of which a lot of us have already walked. And the old shall become as new....
Just my take, as I am not a representative of the parent company, Zabaware, Inc.