Imitation is the sincerest form of flattery, although on the Web it can be followed by the threat of litigation.
Wired reports that travel search site Kayak.com sent Microsoft a "legal letter" this week based on Microsoft's Bing travel search tool looking too similar to its own. While the Farecast-powered travel search provides differing results from Kayak's, the company is citing its similarity in look and functionality.
A Microsoft spokesperson rebutted the allegation, telling Wired that the latest design was a joint venture with Farecast and the Bing team.
Microsoft redesigned its Farecast travel search engine in conjunction with the launch of Bing.com in late May. Both it and Kayak have the same basic query layout, along with results that can be quickly filtered with sliders and check boxes that sit on the left side of the screen. The two also share certain color patterns and design elements.
That may not be enough to hold up in court though. U.S. copyright law protects creative work that is put in "tangible form." For copied imagery and text that distinction can be easy. However, when it comes to Web design, things begin to get murky. Its defense often relies on the comparison of the code of two sites, as well as the infringement of any company brands or trademarks.
"It is a hard case for Kayak to make because all airline reservation sites look a lot alike--they are trying to convey the same information, so this is not surprising," says Jim DeLong, who is the chairman of the intellectual property practice at Kamlet Reichert's Washington, D.C., office.
"It looks like a legal area called 'trade dress.' And Kayak would be limited to arguing about the use of grey in the left column, and about some of the typography in the same place."
Travel search remains one of the most profitable parts of Microsoft's search business alongside its local and shopping search engines. Microsoft purchased Farecast in 2008 to boost its profile in the travel search market. It was then integrated deeply into Microsoft's MSN properties, and now Bing.
Other high-profile design similarities in recent history have involved AOL's beta site, which looked suspiciously close to Yahoo's front page; Google's Chrome browser logo; and Croatian Radiotelevision's BBC-like redesign.
Note: This story was updated at 12:07 p.m. PST with comment from Jim DeLong.