Y'all are too sour abour entrepreneurship done on private time. If you had a problem with promoting Dilbert or his creator's business, you wouldn't be here. Sayonara to the whiners! Reflexive comics rock.
The way I see it: The comic strips are totally free. The plug didn't make the strip less funny. You're still free not to use the promoted service. Not much worse than ad banners, and surely a legitimate way of earning money.
Come on, gang. At least he doesn't have to worry about getting sued by somebody else for making fun of THEIR website that just happened to have the same URL as what Scott chose. This way, if nothing else, he can sue himself.