Diane, you make a good point, and Peepsie's question is the crux of it all for me.
people don't buy newspaper cartoons, but the newspapers do, whether that is through a syndication set-up or as original commissioned work for the papers in question. Money is earned by the artists. I don't see how Comics.com can be publishing so many top quality strips without remuneration of some kind to the artists. I would certainly not place my work with them purely for exposure, and I don't believe anyone else would do that.
I assumed part of the subscription (and I was a subscriber) went towards artist royalties, and now I assume that comes from the advertising revenue. I've no idea how it works, but if I thought this work was available without financial reward to the creators, I'd be fuming...but not at comics.com so much as the creators themselves for enabling that to happen.
If, however, the artists are being paid through the site, then there is little to complain about. I understand your frustration, Malcolm, but as one cartoonist who has never worked for any form of royalty income in my entire career, I've always been happy with a one-off fee for anything I've produced (I do charge extra for certain usages and assigning copyrights), I've never had to worry about repeat fees of any description for work I've done in the past. That's not to say I wouldn't be happy with receiving it, of course.
I've often had to 'correct' potential client's assumption that because we do something that most people regard as 'doodling', and not real work, that payment can reflect that. And I've had more than a few apologies (and eventually very happy customers) out of doing so. Then there have been the slightly rarer clients admittedly, who fully recognise the worth of time-served and talented artisans, and will not only pay accordingly and willingly, but even occasionally tell you that they would have paid more (this has happened to me twice this year, and one of them actually did pay more).
I do have a framework of fee rates which I usually apply to each commission, but the beauty of being self-employed is that I can charge what I like to whoever I like...or dislike as the case may be...and often do.