20. Energy Flow
StumbleUpon, one of the most sophisticated and fun ways to explore new content on the Web, delivers an excellent experience on the iPhone, if you can cope with the inherent limitations of the small screen. Without a native mobile-optimized viewing option, it's a little less than ideal on the iPhone.
One of our favorite file-syncing services, SugarSync added an iPhone app to its offering in 2011. SugarSync gives you access to your files from a multitude of devices, no matter if you store them on your laptop at home, desktop computer at the office, tablet, and so on. You can use SugarSync to stream music, back-up photos, collaborate on projects, and more.