I get the same when I go to vanguard.com. You cannot remove it because it's not on your computer but on the site itself.
If you want to block this in your browser - Use the Firefox Noscript addon: https://addons.mozilla.org/nl/firefox/addon/722/
Or just don't visit the site anymore if you are worried. But basically, Doubleclick is ok though. MANY sites use it. Also read more here about the doubleclick cookies: http://www.doubleclick.com/privacy/faq.aspx
Don't worry to enter the site, it's ok
Edited by miekiemoes, 24 August 2010 - 04:28 AM.