Digital, you really need to relax. I'm not saying become slack in any security areas, but your exhuberance of youth in your job is a little overwhelming at times. LOTS of folks here have security clearances. One of my duties is repairing crypto gear. I can tell anyone I do that, big deal. You want to see something that'll really burn your ass? Check out http://www.jproc.ca/crypto/kg84.html
which contains way more info than I'm allowed to talk about. Also, note the TLD it's hosted on. As for the building Greylocks mentioned, it's been marked on Google Earth before. I don't have the URL handy though.
Debbie, the plain answer is yes, folks in certain departments keep an eye on these boards. Have they done much with anything they've found? Not really. At least we're not living in an Orwellian society like a certain country to the south, where the government carries out illegal wiretaps on a frequent basis. That we know of, anyway.