Quoted from Wikipedia:
Elias Levy (also known as Aleph One), was the moderator of the full disclosure vulnerability mailing list Bugtraq from May 14, 1996, until he stepped down on October 15, 2001. He was the CTO and co-founder of the computer security company SecurityFocus, which was acquired by Symantec on August 6, 2002. He is better known as the author of the article "Smashing The Stack For Fun and Profit", published in 1996 Phrack magazine issue 49, which was the first high-quality public step-by-step introduction to stack buffer overflow vulnerabilities and their exploitation.
After the sale of SecurityFocus by Symantec in August 2002, Levy was accused by many of "selling out" and compromising the high principles of the Bugtraq list. The "Full-Disclosure" mailing list was founded in part as a protest to the sale.