Tag this one “kettle,” “pot,” “black.” The growing prospects of a Google antitrust probe on both sides of the Atlantic has drawn into the fray the search giant’s biggest nemesis: Microsoft. Not surprisingly, what’s shaping up to be the first major tech antitrust battle of the Twitter era is being fought in the public — and, yes, your input is wanted. Within hours of word leaking that Europe competition watchdogs were looking into Google’s dominance in the search market, Google fired back on its corporate blog, defending its image as the benign and innovative force in search. Its blog readers were largely supportive of Google, suspiciously seeing Microsoft’s fingerprints all over this complaint. Among the 15 replies left, one reader writes:

I do think this is backed by Microsoft, they are loosing ground because they have lost the competitive edge. I remember a company named Netscape that had similar complaints about Microsoft and unfair business practices. If I create a better mouse trap and people like it, then why would I change it. People have choices.

On Friday, it was Microsoft’s legal counsel Dave Heiner turn to weigh in on Microsoft’s corporate blog, saying, yes, they’ve been discussing with regulatory authorities Google’s dominance and even bemoaning that some of Google’s businesses “appear to raise serious antitrust issues.”

Three times as many people responded to Heiner’s blog post, nearly all with incredulity. Microsoft, a champion of the little guy?, they sputtered.

Make no mistake, antitrust battles are fought with high-powered lawyers and PR teams that spin, attack, then spin and attack some more. Fascinating to see these two giants to draw the public so quickly into the debate. Courting public opinion will be crucial as this titanic clash plays out. Where do you stand?