Apart from that I think that using the block form of map would make it a whole lot more obvious which part of this is being iterated over, which I know you'll disagree with, possibly vehmently :), I think description of how it works in this post is infinitely more useful as a comment that the original.

I tried (really hard) to understand the code without the original comment. I eventually gave up and read the comment, and frankly was none-the-wiser. Maybe in the context of the surrounding code it might have clarified more. Once I read your description here, I finally understood what the code was doing, and how it was doing it.

On that basis, I would use the description from this post, including the update, in preference to the original.