The option they NEED, and the one I described, is simple: Only accept cookies originating from the same server as the page being viewed. Or perhaps, disallow cookies with non-HTML files. I can't think of any good reason, other than ads, to send a cookie with a graphic image.
Actually, I co-maintain a small site which uses cookies in off-site non-html files. This is used to customize the style sheet used in some otherwise static HTML documents placed on a separate server. The style sheet doesn't set any cookies, of course, but it does rely on the browser to send the cookies as part of the HTTP request. I can think of similar uses of cookies to choose between different image files based on the cookies set in the browser.
Ignoring "SetCookie" headers in off-site/image file responses, as you suggested, is probably okay, although someone could probably think of a non-advertising related case where that functionality is useful. Just make sure not to kill the (IMHO very) useful functionality described in the previous paragraph.
You do realize that a license with a clause such as this one fails criterion 6 of the Open Source Definition (aka the Debian Free Software guidelines) which states that
The license must not restrict anyone from making use of the program in a specific field of endeavor. For example, it may not restrict the program from being used in a business, or from being used for genetic research.
Slashdot Mirror
HardwareZone did a review of this a couple of days ago. They weren't too happy about it.
Otto wrote:
Actually, I co-maintain a small site which uses cookies in off-site non-html files. This is used to customize the style sheet used in some otherwise static HTML documents placed on a separate server. The style sheet doesn't set any cookies, of course, but it does rely on the browser to send the cookies as part of the HTTP request. I can think of similar uses of cookies to choose between different image files based on the cookies set in the browser.
Ignoring "SetCookie" headers in off-site/image file responses, as you suggested, is probably okay, although someone could probably think of a non-advertising related case where that functionality is useful. Just make sure not to kill the (IMHO very) useful functionality described in the previous paragraph.
You do realize that a license with a clause such as this one fails criterion 6 of the Open Source Definition (aka the Debian Free Software guidelines) which states that
The license must not restrict anyone from making use of the program in a specific field of endeavor. For example, it may not restrict the program from being used in a business, or from being used for genetic research.