Dick, I hate to break it to you, but you're not important enough for the government to track every mention of the word Obama by you. Now if you put the words "Obama assassination gun bomb sniper kill president" all in one post, that might possibly flag something in the datacenter outside Langley, but even then it takes more to be brought to a living human's attention.
All you're doing here is waving your paranoia around for everyone to see.
Fake Edit: I was badmouthing Bush Jr since he started talking publicly about invading Iraq, so I'm long-since in their system. Back in my LiveJournal days, I even used a tool that tracked who visited my LJ, and I had daily visits from a Langley IP address that never posted. I'm sure I'm marked as a subversive somewhere for raging publicly about all the various bullshit things Bush did (and attending a number of protests against the Iraq war).