While Google and Microsoft have been heavyweight rivals for quite some time now, they’re fighting a new battle today, and the gloves appear to be coming off. Never before in my time as a search engine marketing consultant have I ever seen the kind of blunt, open criticism that Google levied on Microsoft with a blog post yesterday afternoon. Does Bing steal search results from Google? Short answer: yes, it appears so.

Google has laid the smack-down on Microsoft, calling them out in public fashion on their main blog–something we’ve never seen before and something most of us would have thought impossible. And yet it’s happened. And it is a powerful indictment, complete with fairly iron-clad evidence:

“Put another way, some Bing results increasingly look like an incomplete, stale version of Google results—a cheap imitation. At Google we strongly believe in innovation and are proud of our search quality. We’ve invested thousands of person-years into developing our search algorithms because we want our users to get the right answer every time they search, and that’s not easy. We look forward to competing with genuinely new search algorithms out there—algorithms built on core innovation, and not on recycled search results from a competitor. So to all the users out there looking for the most authentic, relevant search results, we encourage you to come directly to Google. And to those who have asked what we want out of all this, the answer is simple: we’d like for this practice to stop.”

Wow. That’s a public rebuke.

Google basically set up a sting after seeing some evidence suggesting their results were being copied. They created manual results for ridiculously unlikely queries (like “hiybbpraqag,” “delhipublicschool40 chdjob,” and “juegosdeben1ogrande”), and the results they created had nothing to do with the query at all–meaning they set the first result to be a page that would never naturally rank for the gibberish phrases.

Then they set up some of their employees with Windows machines running Internet Explorer 8 as well as the Bing toolbar, and asked them to type the gibberish queries on the Google home page.  After a few weeks, Bing suddenly began returning the exact same (poorly-matched) results.

The conclusion Google draws is that Microsoft is using the user data from their Bing Toolbar to directly copy search results from Google. How, they ask, could there be any other explanation for the similarities? And I have to agree with them. I think Microsoft just got caught with their pants down. The trail of evidence and screenshots is like an episode of CSI. Just take a look at some of the comparison shots:

Or these:

Microsoft disagrees with Google’s conclusion, of course, and posted their own rebuttal. Sadly, the Bing rebuttal is full of vague language and doesn’t remotely get into the nuts and bolts the way that Google’s post did. It’s basically a long-winded version of a simple denial. Instead of addressing the direct claims, they took a more argumentative tact:

“To be clear, we learn from all of our customers. What we saw in today’s story was a spy-novelesque stunt to generate extreme outliers in tail query ranking. It was a creative tactic by a competitor, and we’ll take it as a back-handed compliment. But it doesn’t accurately portray how we use opt-in customer data as one of many inputs to help improve our user experience.”

Of course, the whole incident has quickly led to the usual back and forth between the two groups of Google and Microsoft fan-boys. Many have been quick to point out how much of Google’s current search interface is “borrowed” from Bing–which is something we said back when the interface launched. There’s such a fine line between imitation and outright stealing. Google says potato, and Microsoft says po-tah-to.

But make no mistake: the implications for you and I are enormous. What Google is suggesting is that, with some queries, Bing may be relying more on Google’s results than any other factor (or perhaps there are no other factors whatsoever). So your Title Tags, your video Descriptions, your hours of keyword research… could all be in vain. That’s what Google is saying, right? That Bing is straight-up ripping results from Google. After all, the queries never appeared on the top-ranked site’s pages or code… never appeared in anchor text linking to those sites.

They’re supposed to have an algorithm, right? Weighing links and domain age and keywords… Think about all the many factors that impact a site’s ranking–all the things you do in a typical SEO project–and then think about all of that being completely disregarded. That’s why this is a big deal. If it’s true, and Google is right about what Bing is doing, then most of us have been wasting our time when it comes to SEO and Bing results. I can see a whole lot of people being very mad about this kind of thing.

Something tells me this story isn’t over, and I’m guessing there are many people who have yet to weigh in, and I’ll be curious to see whether a story like this breaks out of the tech news world into the mainstream. What do you think? Is Bing guilty or is Google overreacting?