After tracking various data for a while, I’ve gone ahead and dropped AdSense from the site, replacing it with another PW block.
Primarily, AdSense isn’t as good as it used to be. Or, in fact, it’s about the same; but people aren’t as into clicking on text adverts as they used to be. So, while a given click is good for anything from about a nickel to ten bucks [and there's kinda no guessing], impressions make about one cent per thousand.
Also, AdSense remains contextual. And that’s meaningless when most of the text is in an image. As far as google.com know, a given strip is its title and its hovertext; since neither of those necessarily has anything obvious to do with a given strip, the adverts AdSense throws at the site can be totally generic, or specific to something immediately unrelated. Meaning from an ethical standpoint that the advertisers are ultimately paying anything from a tenth of one percent of a penny to ten bucks to advertise something which has nothing to do with us.
Meanwhile, since I’ve been doing some advertising myself, I’m not too sure about something. Technically, according to the ToS at google.com, I can’t generate traffic via Paid to Click links. Which is fine: I don’t do that. But, depending how you take that, it could be argued that spending any amount of money to get any amount of users to hit a site, at a tenth of one percent of a penny per impression, might constitute paying for the traffic which leads ultimately to getting paid. Of course, a similar argument could be made that linking to the site from another site, after paying an ISP to get you online, is about the same thing. So I dunno.
Actually: no one knows. No one at google.com knows. The rule’s in place, but I can’t find an instance in which it’s been enforced over what I’m doing. So, maybe it’s nothing. Then again, I’ve heard of them dropping people who reload their own sites just in the process of writing something [like this], saving the draft, and previewing the results; since I and everyone whose site isn’t a mass of typos do that, it becomes a stupid rule which you might get in trouble for breaking.
Anyway: I haven’t dropped AdSense fully; I’ve still got it on other sites. But, here, on a webcomic, it’s not really the perfect fit. And, since removing it left something of a gap, I’ve replaced it with another PW thing, which more often than not advertises other webcomics—so it’s at least kinda ontopic. Also, like it or not, PW adverts automatically open in a new tab; I like it because that allows people to stay on this site and keep an eye on what’s happening over time.
Of course, as I write this, there’s no advert in the new block yet. It’s been in the code for less than a day now; it’ll take at least a couple days to work its way through the system, from which most advertisers place bids. That’ll presumably change soon enough.