He wrote in 2012:
Rachel Bernstein forwarded [an] email you sent to a Sidecar Studios address. As she said to me, we really need to update things and let people know that Sidecar is no longer in business.
I was impressed though at the work you've done with the Imperialism wiki. And of course it's nice to know that the old games still have some dedicated fans.
Feel free to write anytime, with questions or whatever. Best wishes.
billspieth"at"gmail dot com