Office Live, which runs sites such as Legalofficelive.com, Realtorsofficelive.com and Accountantsofficelive.com, offers free professional advice to consumers and offers customer leads to businesses. The company is seeking an injunction to prevent Microsoft from using the "Office Live" name.
The lawsuit comes at a time when Microsoft is working to get itsestablished in the market.
In November, Microsoft's Internet-based business software,, with such features as customer management tools, e-mail accounts and Web site building and hosting.
Office Live, based in the Los Angeles area, registered the "Office Live" trademark in 2002. It initially filed its lawsuit against Microsoft in December in U.S. District Court in California but agreed to withhold serving the suit to allow the companies to pursue settlement negotiations.
When those talks broke down, Office Live served the software giant with a lawsuit earlier this month.
"It is shocking that Microsoft would have so little regard for another company's intellectual property rights that it would select a name belonging to another company," Lenny Targon, Office Live chief executive, said in a statement. "Online software may be the next big thing, but Microsoft has no right to use our trademark without permission."
"We don't think Office Live LLC has a trademark, or that we are infringing any rights asserted by Office Live LLC," a Microsoft representative said. "Now that the complaint has been served, we will vigorously defend our legal position. We also will seek to invalidate Office Live LLC's claim to trademark the phrase "Office Live" in its common connotation."
Microsoft said it views the word "Live" as a descriptor, such as in the case of "AOL Live" and "Vodafone Live," and has indicated that stance to Office Live LLC in previous discussions.