Four companies on our 2011 Most Innovative Companies list went public in the last year: Groupon, LinkedIn, Pandora, and Zynga. But only LinkedIn remains well above its offer price, boosted by new initiatives. LinkedIn Today lets members curate daily news roundups to showcase their expertise, transforming the professional network into a must-visit hub of information sharing. "Everybody wants to be better informed, better at their job," says LinkedIn SVP Deep Nishar. Metrics show users now follow links on LinkedIn more than via Twitter.