Blogging didn’t take-off; it was mostly led by corporate communications. Started seeding blogs with non-work related blog posts (e.g. personal growth). CIO was an original blog; CEO does a blog, but it’s treated like a news story (he now responds to comments).
We do a weekly news show (Good Morning Cigna, two-minutes long) as well as a weekly spotlight video on employees. Our internal social channel is Cigna Social (using SharePoint 2010) and it is completely open to all employees to post without approvals (we monitor posts and 9 times out of 10 anything questionable is self-policed by employees).