Google is set to boost its search offering by integrating results from a number of its search engines. The company has announced that it is moving towards a "universal search model" - even though it admits that it is still a long way from offering the ideal of a single set of results culled from all its engines.

Users have been warned not to expect instant change, however. Google said that the changes would be subtle and gradual.To this end, Google is putting in place a new infrastructure to handle the intensive computational tasks involved in providing integrated results. An upgrade to the results ranking mechanism is also being rolled out.

All search companies are looking to make such a move. Google and its competitors (like AOL, Yahoo and Microsoft) offer a set of specialty engines that deliver only news articles, photos, local business listings, blog postings, maps and video clips.

These companies have long recognised that it is highly inconvenient for users to have to use different engines for the same query, particularly because it is often relevant to see, for instance, web pages, images and maps to satisfy searches. Moreover, studies have shown that many people don't even realise that these companies have specialty search engines beyond their main web search sites.

"It's an acknowledgement by Google that users aren't going to these vertical search sites where Google has lots of valuable links to crawled content," said industry analyst Greg Sterling of Sterling Market Intelligence. "This is a way to expose users to these links without having them go to the vertical engines."

Thus, Google and its competitors know that in order to improve the average user's search experience, they need to collate results from their different engines. As the operator of the world's most popular search engine, Google has probably more riding on this than any of its competitors. Almost all of Google's revenue is generated from ads it runs along with its search engine results.

The integrated results will be applied for now to searches conducted on the main Google.com web search engine only, a Google spokeswoman said.

Google's competitors have also begun integrating results from their engines in various ways and with different approaches, but with the same goal in mind: improve the search experience for users.

The universal search improvements look incremental, considering Google has been including results from some of its other engines in Google.com results for some time, Sterling said. However, it will be interesting to see how users react to a more deliberate and obvious effort to integrate different engines' search results, he said.

It will also bear watching how they respond to having to scan over more result options in the first page of results, he said. People usually give a quick scan to the first five results and rarely scroll down the page or click on over to the second page of results, Sterling said.

Google also updated its homepage design and tweaked navigation features to accommodate the collated set of results.

Finally, for those interested in learning of Google's latest experiments, Google has released a service called Google Experimental on its Labs site.