No it's not. Let me wax poetic for a little bit, and encourage you to never say that to anyone again. I've said this to other web comic and other artists in the past;

As an Objectivist, you do something that has value to me. I enjoy the comic (as I do a variety of other web comics I read daily and support ), I look forward to the minute it takes to read as my morning email is downloading on my other computer. I cannot live by my own ethical standards and not provide value back. In the newspaper my favorites never know. They don't have a tangible connection between those who find their work of value. Fan mail, certainly, but not a free exchange of value given for value received. With the technology now in place I can exchange value directly, and appropriately to someone like you who is the direct producer of what I value.

I'm a Technologist who has been working in the computer industry for nearly 30 years to address that challenge. My ability to pay-pal money directly to you, in a tiny payment or $20, represents to me the first step of the fulfillment of one of the reasons why I learned to program in 1973. We are mutually participating in a revolution in the patron/artist relationship through technology, and in the process helping to destroy the oligarchical control over style/culture/thought/art that has been the hallmark of the last 150 years, since direct patronage flagged. We're proving that Techno-Anarchy is a valid grounds for human interation, beginning now.

As an Anarchist I want the community I am affiliated with to contain art, humor, and perspectives that you (and others) provide. To insure that, I have to contribute what I can to the community. I happen to make a good bit of money, so the value I can add to the community is the mechanism of exchange that allows you to continue to produce the art you produce, which otherwise does not provide a direct food/fuel/shelter component to the community, but is just as valuable. I am not giving you anything, I am exchanging the value I receive from my work for the enjoyment I get from your comic. You don't stipulate a rate of excahnge, so I make the value calculation myself and that's the result. And, since I cannot coerce anyone to do something, in this case I'm cheating somewhat ethically by paying for the last month or two's enjoyment, instead of providing commensurate value at the time of consumption. But that's your challenge too, since you have not yet instituted a pay-per-strip model yet. To the Technologist point, we're working on making that so painless you will be able to in the not too distant future.

Long winded way of saying "Hush up, say 'thanks' and that's all, and take the money". And keep making me smile.