It isn't clear if they are real, but if they are they happen to be nearly 1000 pages of complex documents about Mitt's investments during the past decade (certainly not complete). The folks hosting them are asking for a crowd-sourced effort to figure out what is likely to be going on
On first blush the claim is there is a lot of tax dodging going on through Cayman Island investments. The existance of things like that could be very harmful to Mitt - which could explain why he won't release his tax forms for a reasonable historical period. The ball is in his court - if he doesn't publish them it may be reasonable to suspect he really is hiding something nasty..
Already there appear to be some interesting issues... and perhaps Mitt and his wife would have to amend their taxes. More important, if true, it just looks sleazy in the worst corporate way.