Microsoft (NASDAQ:MSFT) is raising the stakes in its battle against Google (NASDAQ:GOOGL). Don't be surprised if it backfires.

The software giant rolled out Scroogled.com, a website with an accompanying video that chastises Big G for turning Google's Shopping hub into comparison shopping website that only features paid ads.

Bing has a point. Google Shopping seems less useful since its springtime tweak. However, Microsoft may be barking up the wrong tree by suggesting that Internet surfers turn to Bing for honest search results.

Search Engine Land's Danny Sullivan is taking the Scroogled campaign to task, suggesting that Microsoft's shopping portal is just as guilty.

Mr. Softy's portal for interested merchants begins with a level playing field introduction.

"With Bing Shopping, you can drive traffic to your sites for free, potentially displaying your online products to more than 93.6 million unique searchers making decisions with Bing."

Cool. However, that's immediately followed by an italicized disclaimed that Bing is not accepting new merchants for its free program at this time. The only way for new merchants to list their products is through its partner Shopping.com.

Now, eBay's (NASDAQ:EBAY) Shopping.com isn't a free site for merchants. Businesses need to pay a minimum of $100 to fund their Shopping.com accounts to get started. Merchants than pay for every click that Shopping.com and its partners -- including Bing -- delivers.

There's nothing wrong with this.

Even Bing's own merchant portal -- promising "higher visibility" for paid offers that are highlighted throughout Bing Shopping -- is perfectly legit. Bing and Google are search engines. This is how they make their money.

However, for Bing to call out Google's practices at a time when it's not exactly a free marketplace is bizarre to say the least.

The move also opens the door for Google to fight back.

Why pay for Microsoft Office's productivity suite, when Google Drive offers a free cloud-based platform for the creation of spreadsheets, presentations, and word processing documents? Why should licensees be paying for Windows and its various operating systems, when Google's Android is open source?

Does Microsoft really want things to get that far? The Scroogled campaign was probably a smart idea at one time. You have to love Mr. Softy's timing, rolling this out just as the holiday shopping season is drawing Internet users to shopping portals. However, it's not cool to be calling out something as black hat when your own hands are dirty.

Longtime Fool contributor Rick Aristotle Munarriz has no positions in the stocks mentioned above. The Motley Fool owns shares of Google and Microsoft. Motley Fool newsletter services recommend eBay, Google, and Microsoft. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.