Eavesdropping has gone from peeking in windows to a $5 billion business. Western companies make sophisticated technology for what they call "lawful intercept." Is it also used for human rights abuses overseas and invasions of privacy at home? Thirty-five US government agencies and 43 countries attended the latest US trade fare for high-tech surveillance, one of five events held annually across the world and called "The Wiretappers' Ball." That's according to Sari Horwitz, investigative reporter for the Washington Post.