The memo doesn't add new facts, just new spin. Naturally, because the spin is more lurid, it's what a lot of the climate blogs seized on.If the faked document happened to be produced by a climate activist or scientist (as some are already suggesting), then the leaked Heartland documents will go down in history as one of the more spectacular own goals in the history of the climate debate (with the consequences proportional to the stature of the faker). The faking is likely to overshadow whatever legitimate questions may have been raised by the release of the documents. Imagine what would have happened if the UEA hacker/leaker had made up a few emails to spice up the dossier.
More generally, the episode already illustrates much of what has become of the activist wing of the climate science community -- Apparently, reality is not good enough, so it must be sexed up. This sort of thing feeds into the worst imaginings of skeptics and blinds them to the fact that there are real issues here despite the frequent over-egging of the pudding.
It will be interesting to see how this develops as it appears that the faker left plenty enough fingerprints to be revealed in due course. The collateral damage is likely to be significant among the media and the overeager blogosphere. Stay tuned.