Looking for gov-based social media data

I’ve been contacted by a colleague looking for some data about the adoption of social media technology by government. Here’s her question, prompted by a presentation she’s preparing:

“Are you aware of any research that reports on the level of involvement of the US government (either growth in recent years, or something that compares corporate vs public organizations). I hope other US information covered quite well, but wanted to comment on how (1) US government is lagging behind corporate use OR (2) US government’s use is growing.”

What say ye, GovLoopers? Is such data available?