Well, it looks like he hasn't made any kind of public appearance (in the aquarium hobby context) in at least a year. Though it might sound obnoxious coming from me (given that, a couple years ago, I zealously campaigned against his merit/reputation as a researcher)... but I do hope he "comes back" to the hobby. Despite his apparent blunders and spotty attempts at controlled research, I still think that what he originally had to offer the hobby is still what he has to offer... delightfully astute, entertaining and informative musings and observations on reef keeping. I wonder if his absense was promoted by a failure to obtain the PhD he had been seeking for almost a decade. Many universities in Texas have a 10 year time limit on any PhD program, and so he may have just run out of time. I think it would be unfortunate if that were the reason he has "left" the hobby. It seems to me that most people who are considered successful aquarists don't have PhDs in marine biology. I'm certain people would still read his articles even if he's not officially a "scientist." They've been doing so since 1998, before he even started his PhD program.
But, of course, I'm speculating as to the reason for his cyber absence. For all I know, he was kidnapped by aliens or maybe he went to live with the Amish. Or, maybe he just wanted to leave in a shroud of mystery for the poetic effect... I've always been a fan of such exits myself.