@Ipstenu - I'd agree with that sentiment. I have ads on my site, and I get money from them, but I'd hesitate to say that my site "makes money". I do earn a little more than my hosting costs, but not by any significant margin.

That said, I don't have any problems with them tweaking the signup process to encourage more people to thinking about what the service is worth to them. I'm sure that the Akismet service uses more resources than most people realize.