- Shaw is the cable monopoly in the west. Shaw used to have a presence in Ontario but they did a big asset swap about 10 years ago.
- A few areas have different cable monopolies but they're vastly smaller than Rogers/Shaw. Cogeco and Videotron, I think.
- Beyond Rogers (who bought Microcell a.k.a. Fido) and the smaller players, Bell and Telus actually teamed up and built their own GSM network. I think it went live shortly before the 2010 olympics.
- As far as I know Bell and Telus both operate their own CDMA networks across Canada. In Ontario, at least, you've been able to get CDMA service from both for a long long time.
- I heard about the GSM network, but IIRC there is some sort of transition period going on right now. Also, I've heard varying reports about it. I wasn't sure if they actually had a GSM network or if people were talking about them not using CDMA for 3G internet.
Re: the GSM network, I thought it was kind of ridiculous at first for the two carriers to build an entirely new 3G network when their CDMA works just fine. The speculation I heard was (1) they wanted to sell the iPhone (2) roaming revenue for the 2010 Olympics. Neither seemed like enough reason for such huge expense though. I can't find much solid information but I'm willing to bet you're right and their GSM network is available in a few places nationwide.
Rogers does: cable tv, ip phone over cable (ala Comcast in the US), cable internet (which IIRC it own the only coax last-mile lines in the areas where it is a monopoly -- I think that west Canada has a different cable monopoly), the only gsm carrier in Canada+, a chain of video rental stores that competes with Blockbuster Canada.
Bell does: phone, DSL++, and the only CDMA cell carrier in Canada+++.
+ At the time I was living in Canada, there were many smaller GSM players, but they had all been bought out by Rogers, so you largely just had different branded GSM services from the same provider. More recently there have been at least two new GSM players (Wind and Mobilicity) though I believe that their coverage area is mainly just the Greater Toronto Area. [Of note is that Bell and Rogers use the same 3G bands as AT&T does in the US and Wind/Mobilicity use the same 3G bands as T-Mobile does in the US.]
++ The last-mile DSL lines were being sold to 3rd-parties ISPs as well as Bell itself being an ISP on those lines. See me ascii-art diagram in the other thread.
+++ Similar to Rogers, IIRC there were a couple of smaller players that were bought out by Bell so that all of the CDMA carriers were under the Bell 'umbrella.'