Woohoo! Just discovered I can get daily Calvin and Hobbes in an RSS feed in bloglines. Seeing as I've bought almost all the Calvin and Hobbes books (that is, one copy of each, you understand), and the chances of me ever clicking on an ad on the web site are almost nil (I am virtually impervious to banner ads), I don't feel bad about the loss of traffic to their site.
I never liked comics by e-mail, but an RSS feed is perfect. These feeds are not at all official, but they aren't illegal from what I can tell - they link to the original images, so don't involve copying images (which would break copyright). In essence, they are simply the URL to today's comic image, which is then downloaded by your browser/feed reader. If these companies had got themselves sorted sooner, they could have produced their own feeds - complete with a revenue-generating one line text ad, which no one would have objected to. How come these people are so slow?