Google announced some improvements for how it indexes smartphone content in mobile search. Googlebot-Mobile will now crawl with a smartphone user-agent in addition to its previous feature phone user-agents.

This, the company says, will allow it to increase its coverage of smartphone content, which means a better search experience for smartphone users.

“The content crawled by smartphone Googlebot-Mobile will be used primarily to improve the user experience on mobile search,” explains software engineer Yoshikiyo Kato. “For example, the new crawler may discover content specifically optimized to be browsed on smartphones as well as smartphone-specific redirects.”

“One new feature we’re also launching that uses these signals is Skip Redirect for Smartphone-Optimized Pages,” adds Kato. “When we discover a URL in our search results that redirects smartphone users to another URL serving smartphone-optimized content, we change the link target shown in the search results to point directly to the final destination URL. This removes the extra latency the redirect introduces leading to a saving of 0.5-1 seconds on average when visiting landing page for such search results.”

Google stresses that webmaster should treat each Googlebot-Mobile request as they would a human user with the same phone user-agent. Google references a blog post from the Webmaster Central blog earlier this year about making sites more mobile friendly.

In that, Webmaster Trends Analyst Pierre Far wrote, “To decide which content to serve, assess which content your website has that best serves the phone(s) in the User-agent string.”

The new smartphone user-agent strings are as follows:

Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_1 like Mac OS X; en-us) AppleWebKit/532.9 (KHTML, like Gecko) Version/4.0.5 Mobile/8B117 Safari/6531.22.7 (compatible; Googlebot-Mobile/2.1; +http://www.google.com/bot.html)