TexasCHLforum.com

Wow. That was unexpected :(

Looks like he succumbed from complications related to a heart attack.

I found this from Rob Pincus, who knew Mark very well (Rob made some great videos funded by Mark). Sorry for the weird URL, it's the only one I can find right now.
http://word.office.live.com/wv/WordView ... ghead.docx" onclick="window.open(this.href);return false;