Reasonable on 02 February 2010
They need to keep the reviews from now defunct sites to maintain consistency to the displayed score. If they removed them then if you actually looked at the shown reviews and compared them to the MC average it might look wildly off.
What they should do though is clean up the site to clearly indicate non-active reviews and remove the links that lead to no longer reviewing sites. I see no reason why you couldn't have a list of reviews that are 'active' and a list that are 'historic' or something like that - i.e. you can't open them and get to the original link.
Try to be reasonable... its easier than you think...
