In July of 2008, both Reddit and Digg launched their new mobile sections at http://m.reddit.com and http://m.digg.com.
With the rising popularity of web browsing, social media news sites, and iPhones, a mobile section is fast becoming a feature every good social communities must have.
Twitter also has a mobile version at http://m.twitter.com (Once I visited the mobile page for Twitter, I had to clear my cache to get back to the regular twitter page).
Other Social Community Mobile Pages:
If you are aware of any other social communities that have launched mobile pages please comment below.