I agree, it may not be tax related, more subsidy.
Here's my take: It makes no sense this change being announced now, but taking effect January 2009.
This is very likely similar to the conditional donation arrangement, announced in plenty of time BEFORE the actual government implementation of new laws took effect, so that the 'publishers' would not put 2 and 2 together and realize the change was not actually motivated by the scripture "You received free, give free".
There's something more to this, and I'm just not sure what it is, but it will become clear sometime in the next 8 months. We just have to keep our eyes and ears alert, so that we put 2 and 2 together at the right time! The GB and their lawyers want this to be totally off the radar when the real reason becomes clear...