While I appreciate the need for you guys to get advertisers, I would just like to say:
  1. These adverts are not particularily useful for anyone outside the US,
  2. Is it necessary for all the adverts (and Amazon book references) to appear on the "Post Comment" page? I never look at the adverts when I am typing in my comment, so they are effectively a waste of bandwidth.
As I said a few days ago, most of us in NZ (especially broadband users) pay for the amount of Mbytes that we download.
How about a 'PayPal' account that some of us can use to donate without lining the pockets of our local telecommunications companies?
Unless you have disabled file caching in your browser the ads will not cause a financial losses for you. You can also increase the file cache to make sure that there is enough space and the browser never has to download them from the server (after the first time).

Of course there is always the option to disable all images (sorry guys)... browsers like Opera have a convenient button for that. It also shows how much data has been downloaded per page.