According to a Bureau of Labor Statistics report from March, 2012 there were 21.2 million Veterans in the US, and of those 2.6 million are Veterans of post-9/11 operations.
One of the things that has proven to be a significant obstacle for many Veterans is translating their military skills into civilian skills. No one in the civilian world cares about your duty assignments and awards. You have to translate the awards/medals into what result your drove that led to the medal. Whether it was a reduction in deadline vehicles in motorpool or an increase in report production in the SCIF, focus on the tangible results you drove, and the responsibilities you took on, especially all the “extra” responsibilities we all take on aside from our primary MOS.
I have seen some US Military members maintain LinkedIn profiles, and that is certainly a good idea. Not really as a place to track your military career, but definitely as a way to begin to build your network that will proven powerful in the future.
A recent entry in the professional social network scene is RallyPoint, and if you are currently serving it is well worth taking a look.