I have just read this article over at the Google Webmasters Blog, I guess it`s nothing to be concerned about right now, but over the next year or two, it may have an impact on a lot of websites.
Over the years, Google has used different crawlers to crawl and index content for feature phones and smartphones. These mobile-specific crawlers have all been referred to as Googlebot-Mobile. However, feature phones and smartphones have considerably different device capabilities, and we've seen cases where a webmaster inadvertently blocked smartphone crawling or indexing when they really meant to block just feature phone crawling or indexing. This ambiguity made it impossible for Google to index smartphone content of some sites, or for Google to recognize that these sites are smartphone-optimized.