How Powerful is the Turn-Off Power of Spam?

JayBonci asks: "Here's a question to the Slashdot readerbase. How powerful is the turnoff power of spam? With an upcoming political election in the United States, and a nation not very-well defended against mass unsolicited emailings, what kind of anti-marketing medium is spam? Could a spammer push out millions of: 'V0te for G3orge W. Bush!' or 'J0hn Kerry for Presidnet@', in the hopes to turn off (or on) voters. Spam marketing penetration is terrible (I've heard figures like .001%), but how powerful is its anti-marketing capabilities? An interesting discussion for the Slashdot audience." How often do you make the decision to NOT buy something form a company because you know they engage in spamming activities?