> I'd rather not. It introduces a pretty big conflict of interest (for example, Gruber would probably think twice before writing something negative about a former sponsor when he's on the record endorsing them)

Generally the companies that advertise on his site are companies that his readers would find useful, but generally aren't the kind of companies that he discusses in his blog posts. Although [I believe] he has had Microsoft and Google products advertise on his site periodically, and his coverage of those companies has still been on his own terms.