REDMOND - Microsoft Corp. is giving its Web browser software its first major upgrade in years, amid signs that Internet Explorer's market share is eroding.
The release late Wednesday brings Microsoft's browser more in line with competing products such as Opera Software ASA's Opera and Mozilla Corp.'s Firefox. Internet Explorer 7, or IE7, adds features such as tabbed browsing, which lets people open several Web pages without cluttering their desktop with multiple open browser windows.
Microsoft has been heavily testing the new browser, releasing five beta versions over 14 months, and has periodically offered security updates for IE6, first released in 2001.
Still, a lag of more than five years between official releases has cost the company. Web analysis company WebSideStory estimates that Internet Explorer's U.S. market share is about 86 percent, while Firefox commands about 11 percent of the market and smaller offerings account for the rest. Two years ago, IE had about a 93 percent share.
Matt Rosoff, analyst with independent researchers Directions on Microsoft, said Internet Explorer is important to Microsoft's business because most people believe an operating system should include a way to immediately access the Web.
Still, he said, Microsoft might not have seen much reason to spend a lot of money upgrading sooner since most people continued to use the older version.