It's been a strange few weeks for us carrier-watchers. First Verizon announced it was going to open its cell network to all "approved" devices, then Comcast announced that it has become buddies with BitTorrent and would switch to a protocol-agnostic method of managing network capacity by year-end.

These are the same companies that have argued they could do anything they wanted to with their networks and that no one was going to tell them any different. When a reversal this dramatic happens, it's a good idea to take a closer look -- in particular at the reasons for the change -- and to see how real the change might be.

The reason for Comcast's advertised change of heart is easy to find.

The company had done just about everything wrong when it decided to mess up people who were using BitTorrent on the Comcast network. First Comcast claimed it was doing nothing of the kind. Then, when caught dead to rights doing precisely that, the company still said it was not blocking the traffic, and then on top of that refused to say just what it was doing. This led to a bunch of news stories and an FCC hearing during which cable-hating FCC Chairman Kevin Martin made it clear that he smelled a rat and would make rules to kill the rat.

Comcast clearly has had a foxhole conversion and is trying to hold off FCC rules that might require it to treat its customers fairly (such a terrible fate for a modern carrier). Trusting Comcast’s intentions at this point would take a great deal more faith than I have.

After so many years of locking customers into using only phones that it sold, Verizon's adoption of an open-access network model  is a little harder to explain. It's great, assuming that the Verizon Open Development process does not turn into more of a filter than an open door, just as some people fear that Apple's SDK will.

I've seen quite a bit of speculation as to why Verizon made this move, with the most likely being that the carrier won the bidding for a large chunk of the spectrum in the recent FCC auction -- spectrum that comes with Google-requested openness requirements. It sure would have been a mess if Verizon allowed openness on only part of its network, so using the same rules for all of its customers makes things a lot easier. Thanks, Google!