There are many many companies besides Classmates.com that do automatic renewals. The real key is how difficult is it to cancel?
If there isn’t a cancel button easily available that I can just click and they force you to call “customer service” then I don’t do business with that company.
Think it was stamps.com (btw waste of money unless you ship A LOT) I had to go through the call rep, his supervisor, and then his supervisor in order to get them to cancel.
I signed up in August 2008 for a high school reunion (and found my half-brother and half-sister I’d never met there!) and in Aug. 2009 I also had my credit card charged. I hadn’t realized it did so automatically—since I planned to stay in the program I wasn’t upset, but I did go in and change the billing to one that needed my approval *first*. Wasn’t terribly difficult to do, IIRC.