Others have a harder time establishing a direct parallel between the times Google has been accused of copying and Tuesday's incident.

"Although there are parallels, I think this situation is a bit different. In past instances -- YouTube, book search, news headlines -- Google was not copying from a competitor in order to beat that competitor," said Gartner analyst Ray Valdes via e-mail.

Eric Goldman, an associate law professor at Santa Clara University, said it's noteworthy that Google apparently has no plans to sue Microsoft over this. Google likely realizes that in business, it's fair game for companies to copy competitors, as long as what's being copied isn't legally protected under copyright, trademark, patent or other laws, he said.

However, according to Goldman, Google may have set the stage for end-user lawsuits against Microsoft alleging privacy violations. Google said it believes Microsoft is capturing Google user queries inappropriately via Internet Explorer and the Bing toolbar. Microsoft also denies this charge, saying users allow it to capture this "clickthrough" data.

Ultimately, Goldman sees the spat as the latest in a long string of public opinion battles between the two companies. "They look for every opportunity to tweak each other," he said in a phone interview.