So, acording to the article, AM3+ will have a dual channel memory bus so AM3 cpus can work?.
They dropped a potential three-channel bus in order to allow people to run their old cpus in new mobos? Not a good decision i think, at least on desktops.

I'm all for backwards compatibility, but in this case it doesn't seem like a good idea. Those who buy a new mobo don't usually stick with an old cpu...
Were it the other way around (Letting people use AM3+ cpus on AM3 mobos) then things would be different. AM3+ would have triple-channel bus, and people could also enjoy the new cpus simply by sticking it on their current mobo (no big change in the platform).