MessageLabs, the email-filtering company that Symantec acquired in 2008, posted a set of word maps today measuring the frequency of terms in spam emails from a random one-week sampling of junk mail pulled from the most prolific spam-spewing botnets.

FORBES: The Most Common Words In Spam Email

Only a receiver programmed with the same random sequence would be able to follow the signal as it hopped from one frequency to another.

ECONOMIST: Player-piano pioneer

By changing the frequency of a radio transmission many times a second, causing it to leap around in an apparently random fashion, a radio signal could be made almost impossible to intercept.

ECONOMIST: Player-piano pioneer