s = score(ups, downs)
order = log10(max(abs(s), 1))
and the poster says that "order will always be positive". But that isn't true. It is the logarithm of a number in (0,1], and so is negative or zero. Since we cut the value off at 1 I assume that the score function does something to the votes beyond (ups - downs), scaling the value in a way that makes the logarithm of the score interesting.
`ups` and `downs` are whole numbers, so `abs(s)` will usually be >= 1, like 2654 or something. The log is there to reduce the influence of additional votes after a certain level of popularity. See footnote ^2: http://technotes.iangreenleaf.com/posts/2013-12-09-reddits-e...