Google has added a second mobile bot: Introducing smartphone Googlebot-Mobile, Google Webmaster Central Blog, 15-December-2011.
If you serve mobile phone visitors a different from desktop content experience you may want to:
Here are the main user-agent strings that Googlebot-Mobile now uses:
* Feature phones Googlebot-Mobile:
---SAMSUNG-SGH-E250/1.0 Profile/MIDP-2.0 Configuration/CLDC-1.1 UP.Browser/188.8.131.52.c.1.101 (GUI) MMP/2.0 (compatible; Googlebot-Mobile/2.1;
---DoCoMo/2.0 N905i(c100;TB;W24H16) (compatible; Googlebot-Mobile/2.1; +http://www.google.com/bot.html)
* Smartphone Googlebot-Mobile:
---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)
The content crawled by smartphone Googlebot-Mobile will be used primarily to improve the user experience on mobile search.
* consider which - or create a third variation - to offer smart phones.
* prominently display a 'switch/skip to' nav link for each site version served.
Note: depending on how your site is designed, configured, served the above may not be necessary. Except for consideration* below.
Also, if you are redirecting visitors to mobile based on user-agent you may want to watch to see how well Google does in connecting all the dots.
*It will also be interesting to see how Google handles the general index and the specifically mobile index when serving smartphone query results...