Photocopy degradation + Photoshop blurring/filtering.
I can't make it match exactly, but I can get the same kind of "kinkiness" between individual letters in rotating the document at 0.5% and tweaking some filters and contrast.
In any case, look at the comments here:
bloggers analyze this better than I ever could
There are reports that this CANNOT be reproduced in word processors other than Microsoft word, and comments such as: "The letter spacing is identical to that of Times New Roman as currently distributed by Microsoft (among others). In this font, the relative widths of -- for instance -- lower case "l" and "m" are 569:1593. This is a finer gradation than any Monotype machine ever had. (Monotype owns the Times New Roman design.) Therefore, the memos were not typeset in 1973."
Go to his site and look at the first document comparisons. Then find "187th." The superscript in the word document is aligned differently vertically than in the "original" document.
I also notice that the top of the capitol G in word is very thin compared to the left side of the G. In the "original" the top is heavier than the vertical side.
The more I look at these documents, the less similar they look, and it deeply pains me to say that!