Yeah, if the weekly work isn't enough, you can just email them whatever you want and get them to mark it. They also encourage you to call them (during work hours) and discuss topics with them over the phone. They can summarise each philosopher pretty well for you.
Every few months, there will be a lecture or meetup with other DECV students and the teachers, and they are definitely worth going to. They also have the occasional live forum (which goes for about an hour) after school where you can discuss topics with them and other students using an instant messenger program, usually a few days before each SAC. There are forums on the site where you can discuss things with other students, which can be good to get a few different perspectives. And there are heaps of links to other sites for really committed students who want further study material.
Infact, I'd argue that a committed student could actually score better in distance ed than he/she would in a regular classroom. The only difficult thing about it is finding the motivation to do work when you could be playing online games instead.