This one involves a different sector of online advertisements. Microsoft uses a dynamic online ad code that checks pages for content and displays relevant ads.
But something went wrong. The ads started showing ads for explicit content on mainstream web pages, including sites like WonderHowTo.com, which offers user-generated tips on home improvement and other topics.
Leading tech analyst Michael Arrington noted that some of the offending content went beyond merely being explicit.
"This isn't just R-rated, run-of-the-mill porn stuff," he said. "This is stuff that's still illegal in some states."
Microsoft has pulled the ads, explaining that they were plagued by bugs.
"We are very cognizant of what we want the Bing brand to stand for, and this is not it," said Microsoft's Adam Sohn.
Last month, enterprising web researchers noticed that a simple search for “pornography” on Google activates a contextual ad for Bing.
Such ads don’t really appear unless someone buys them specifically, which sparked speculation that Microsoft — which had already established porn-friendly bona-fides with its new search engine — was cashing in on its connection to adult.
Microsoft denied the accusations.