I thought this might be interesting for some of you who working on mobile versions of websites. According to a post in Google Webmaster Central blog, websites who redirect all pages to the mobile home page are bound to get some type of penalty. For example, redirecting the regular home page to the mobile home page is OK, but redirecting any other page to the mobile home page is seen as a faulty redirect. The article discusses several other types of problems with mobile phone users. I can't post urls so just search google for: 'Changes in rankings of smartphone search results' to get to the article.