Here's a short snippet directly from the CRTC ruling:
As VoIP services provide access to and/or from the PSTN, it is the Commission's preliminary view that they are not retail Internet services, as that term is defined in Order 2001-220, and that the revenues from VoIP services are accordingly contribution-eligible. It is also the Commission's preliminary view that P2P services are retail Internet services and that the revenues from P2P services are accordingly not contribution-eligible. CRTC: Regulatory framework for voice communication services using Internet Protocol
For now, the CRTC is narrowly defining P2P services as those that don't connect to the PSTN and that don't use 10-digit numbers (a.k.a. the North American Number Plan, NANP). The main point with the ruling is that the CRTC is considering VoIP to be substantially the same as "regular" phone service, since the same service is being delivered. It does not seem to take into account any of the differences, however.
Comments from a few others:
The decision is open for public comment in Gatineau on May 19-20 -- which, as Jeff Pulver notes, also happens to be when VON Canada is happening in Toronto. The deadline to notify of your intent to comment is April 16th.