"May face" is the key word here. The SEC is likely investigating the issue to see if he was using Facebook to give material information preferentially to a subset of investors. An investigation is quite far away from being an actual lawsuit.
As for people asking why the SEC goes after stuff like this--the SEC's authority is pretty narrow. We use a very free-market regulatory model for public companies. Instead of telling them what to do, we basically police the information they put out to the public, and depend on the markets to act on that information to punish bad corporate governance and reward good corporate governance. Pretty much the whole authority of the SEC revolves around disclosure.
As for people asking why the SEC goes after stuff like this--the SEC's authority is pretty narrow. We use a very free-market regulatory model for public companies. Instead of telling them what to do, we basically police the information they put out to the public, and depend on the markets to act on that information to punish bad corporate governance and reward good corporate governance. Pretty much the whole authority of the SEC revolves around disclosure.