Since most communications today merge into the Internet, it is very likely for anyone to have his or her secret lost, and not spotted by the counter party.
Recently a public debate erupted in the country regarding "big data" -- actions by the NSA to comb through normal civilian communication traffic in order to find dangerous needles in the innocent haystack. Detractors claim: it is an excuse to snoop on ordinary Americans. Albeit, "big data" is essentially the technology we use in order to spot adversarial communication, and flush it out from Internet obscurity.
Read more: NSA and Big Data (Information Week).