Spam
First, buy hundreds of thousands of shares in a penny stock.
Second, spam the world about the how great the company is and mention that they will present a fail-safe plan for world peace, plus they found a cure for cancer.
Third, as soon as a very tiny fraction of the targeted audience of the spam reacts to the best stock tip they ever received by buying some shares and pushing the price a few cents higher, sell the stock and gain a 30 – 40 % profit!
Lastly, repeat steps 1 - 3 with a different stock.

Today we saw an increase in email that got past our filters. Spammers, good bad or indifferent are always finding ways around the industry filters. Spam filters get updated and spammers find another technique around them.

According to a report by the California Business and Professions Code, the cost to US organizations is more then 10 billion dollars. So, could there be a vested interest in the continuance of this industry?  (yes, but I don’t subscribe to that conspiracy).
http://www.spamlaws.com/state/ca.shtml

Here are a couple of sites I came across while looking up today’s abuser. The first link is a good FAQ regarding stock spam and the various techniques:
http://spamnation.info/stocks/FAQ.html
http://www.qwoter.com/spam.php
http://www.spamnation.info/stocks/