Making sense of Google's cleantech venture

I've been trying to get my head around Google's surprise announcement this week about it getting into the clean energy business. Is it for for real, and if so, why? Or is it just a PR ploy?

While its new foray into the wireless and mobile phone business isn't too hard to understand, getting into the energy business seems like such a stretch for the search giant. Having plumbed the ecotech and business bloggers for reactions, Martin LaMonica at CNET's Green Tech Blog did one of the best assessments of the upside to Google's announcement.