Halfway down the page (at least as of the time I wrote this, which is not the same as the time this gets posted since I write stuff in advance...) in the section "Outside the Yahoo! Network" there is a link to opt out of sharing the information with companies outside the Yahoo! Network.
Maybe it's time to start surfing with images off again, or perhaps somebody can write a plug-in that blocks all 1x1 images.
[Raymond is currently on vacation; this message was pre-recorded.]