Every administration has interpreted this law differently, but the Secret Service has made it a priority to deal with each threat (or potential threat) very seriously. As much as some people would like it to happen (and THERE ARE DAYS), being the president is already a dangerous job, and the president deserves protection. You don't have to be a faith-based fascist son of a bitch corporate whore president to have people hate your guts - Clinton got a blowjob, and how many people tried to kill him that we heard about?
Other than having to deal with the Secret Service and getting an FBI file, nothing else happened to this person. This person was not beaten bloody with bailing wire and electrocuted with car batteries. That this somehow surprises me is a sad commentary on the state of our government, but if this person is to be believed (and I think they are) this was a routine investigation of a threat on the President's life (on average, there are 1,500 of these investigations per year). If this is a wake-up call to the Internet generation that what you say on this website doesn't matter because it's the Internet, then today is the day (I hope) you learn the difference.