Yesterday, Google revealed the next generation of its Web search service, code-named Caffeine.

On the surface, the changes introduced by Caffeine seem mostly cosmetic--rearranging the way that images, video, and news stories are displayed on the landing page, for example. But according to some (admittedly unscientific) early reviews, there are more significant differences under the hood.

For instance, Caffeine is undoubtedly faster than the current Google Search, often coming back with results in about half the time. It also appears to crawl many more pages--sometimes twice as many for a particular keyword. And according to some pundits, Caffeine's results suggest that it also uses a more complex combination of keywords to rank pages.

These changes will be particularly significant for developers, designers, and SEO experts, who rely on understanding how Google's search algorithms work to make their websites more findable.

Some observers believe that Caffeine is more focused on real-time search results. This would make sense, given rumors that Facebook and Twitter both plan to introduce real-time search services, but I can't say I noticed much evidence myself.

It's tempting to see Caffeine as a response to the success of Microsoft's fledgling search engine Bing, especially in light of last week's search deal between Microsoft and Yahoo. But, again, I couldn't see much similarity between Bing and Caffeine. Even so, for the team behind Bing, I'm sure there's no bigger compliment than seeing Google trying to improve its search functionality this soon.