Microsoft has rolled out the much-publicised changes to its MSN Search engine, calling it the most significant upgrade in its history.

A revamped layout gives the website a cleaner, simpler look, the company claimed, also making it easier to distinguish between normal results and paid-for ads.

Microsoft has reduced the number of sponsored results and they now appear in very slightly shaded boxes with a small "Sponsored sites" label above them. In beta tests, Microsoft claims this design significantly increased the amount of time users spent at MSN Search and the number of queries they ran.

Other changes are that the search box now include a pull-down menu to choose between a Web search, a news search, encyclopedia, or stock quotes. Microsoft also claims better performance and relevance of results. And because this is Microsoft, the stock quotes come from MSN Money and the encyclopedia content from MS Encarta.

Microsoft is planning to add to its search soon with more proprietary content, such as music files and street atlases. And it is only a matter of time before it ties the engine in with the rest of its software such as Outlook e-mail messages, PowerPoint presentations and Excel spreadsheets.

Interestingly though, Microsoft has pulled its paid inclusion program where website owners had to pay to get in the MSN search index. We can thank Google for that.

And in fact, you can thank Google for a massive change in all the Web's main search engines in the past month. First Yahoo made significant changes, then Lycos, then AskJeeves, and now MSN. And that's without counting all the sudden changes in Web-mail offerings since Google announced its Gmail service.

Microsoft is also test driving its next-generation search engine that it says will launch "within the next year." Go to http://sandbox.msn.com for a closer look. Microsoft execs have said recently that their vision for the search segment includes the ability to not only search the Web, but also users' PCs and other sources of information. Like the Mac already does then.

The Internet search market has become very attractive in recent years, thanks to search engines' practice of matching ads to individual searches, making the ads highly relevant to the information a user is searching for. Advertising tied to keyword searching was the fastest growing and the biggest of all US Internet advertising categories in 2003, according to a report published in April by the Interactive Advertising Bureau.

Keyword search revenue made up 15 percent of online ad revenue in 2002, and jumped to 35 percent in 2003. The rest of the 2003 US Internet advertising pie was made up of display advertising (ad banners) with 21 percent (down from 29 percent in 2002), classifieds with 17 percent (up from 15 percent in 2002) and rich media advertising with 8 percent (up from 5 percent in 2002), according to the report. Internet advertising for all of 2003 reached just under $7.3 billion, up nearly 21 percent from 2002.

Google leads the search engine market with 43 percent of global Net searches. Yahoo came second with 31 percent and MSN third with 14.1 percent.

However, the game is far from over and Google doesn't have a stranglehold on the top spot of the Internet search market, because user loyalty in the search engine space is thin, said Gartner analyst Allen Weiner. "Right now, Google is a very narrow brand," he said, because it is almost exclusively focused on search services and doesn't have a suite of complementary Internet services the way Microsoft and Yahoo do. With its 170 million users of its free, Web-based e-mail service Hotmail and vast dominance in the Web browser space, Microsoft has a lot of muscle to market its search engine, he said.