Just in case anyone else was initially confused by the way they're marketing / presenting the "new rates"...
The new "sliding scale" basically amounts to an option to pay for X months in advance, at a reduced rate - the more months you pay for up-front, the cheaper the rate. In some ways, this is better than the previous arrangement, because you now have the option to only pay for one month at a time. On the other hand, paying for 12 months of internet access up front is actually somewhat more risky than a 12 month contract; if DOTCO suddenly disappear for whatever reason, and you have a 12 month contract, then you can just stop paying. If you've already paid up front, however, then you have a problem. Of course, I don't see any particular reason to expect them to do a disappearing act, but it is something to keep in mind.
Still, those people who were reluctant to sign a 12 month contract now have the option to pay month-to-month, so maybe that'll make some people happy.