Two things:
1) He doesn't blur his features as Superman. Everyone knows what Superman looks like, and it's the real deal. He blurs them as Clark, and only when someone's taking a picture of him. That way, anyone who happens to find a picture of Clark Kent on the internet or something sees someone who looks a bit different from Superman.
2) When exactly is Clark Kent ever going to be on mainstream TV? He's not an anchorman, he's a writer.
I lied, three things:
3) Lois is a public persona, but most people don't know that Clark and Lois are married. It isn't very advertised, and Lois uses her maiden name in public. I mean, can anyone tell me sans wikipedia if Diane Sawyer is married, and what her husband looks like?