The traditional war for the desktop browsing environment rages on, but over the last few years we’ve seen the rise of what may be an even more crucial platform: mobile. On tablets and smartphones, via iOS, Android, or WP7, users are making their way to web from wherever they happen to be. For that reason the search sites are hard at work optimizing their mobile versions. Bing has demonstrated innovation in this category with the release of highly visual, mobile-centric features – including a lineup of new mobile search features in both the U.S. and UK.

The UK update primarily entails the roll-out of features already available in the U.S., including the auto-suggestion feature for searches, improved listings for local businesses, image search, map directions (for walking, driving, and even public transit), and a fully re-designed homepage. These features were released in the U.S. starting in early 2011, giving us a strong sense of the release schedule in the UK.

Meanwhile, the U.S. Bing Mobile users who access the mobile site through an HTML 5–capable phone (e.g., one running off Android, iOS, or RIM) will receive a slew of additional options. The focal feature in this release is a number of new social elements, including the option to “like” a local business listing, an image, or even an Apple smartphone application. This set of social tools further integrates Bing with Facebook. The companies partnered earlier this year; Google has yet to establish any such deal with Facebook.

Other features included in the June roll-out include an improved layout in the News section that optimizes the headline layout for mobile, a new “split view” in Bing Maps for Mobile that lets users view directions and a visual map simultaneously, and a search history segment during search auto-suggestion.