Think these screenshots of Microsoft's Bing search engine and travel website Kayak look similar? So does Kayak, and an independent software-copyright attorney contacted by GigaOm. Can you tell which is which?

Bing is on the left; Kayak on the right.

Microsoft guards its own intellectual property fiercely, amassing a hoard of patents, threatening free, competing systems and, as the member of the Business Software Alliance, zealously "auditing" businesses that might be pirating software.

But it's been repeatedly accused of not practicing what it preaches:

  • Apple sued Microsoft for copying the Macintosh's "look and feel" with Windows; it lost repeatedly in court and settled other claims out of court.
  • Disk compression company Stac sued Microsoft for purportedly stealing its technology; it won at trial and Microsoft dropped its appeal after agreeing to pay $43 million in patent royalties and invest $40 million in the company.
  • More recently, Microsoft settled a lawsuit over live gaming technology and lost another over XML technology. "Latest Microsoft Patent Describes Method of Losing Patent Infringement Suits" was the All Things D headline on that last one one.