This excerpt taken from the DVN DEF 14A filed Apr 24, 2009.
Why did I receive a Notice in the mail regarding the Internet availability of proxy materials this year instead of a full set of proxy materials?
This year, in connection with new United States Securities and Exchange Commission (the SEC) rules that allow companies to furnish proxy materials over the Internet, we have sent to most of our stockholders a Notice of Internet Availability of proxy materials instead of a paper copy of the proxy materials. Instructions on how to access the proxy materials over the Internet or to request a paper copy may be found in the Notice. In addition, stockholders may request to receive proxy materials in printed form by mail or electronically by email on an ongoing basis. A stockholders election to receive proxy materials by mail or email will remain in effect until the stockholder terminates it.