Kinda nice... makes it easier to find the popular items after they've fallen off the top of HN, and faster to skim (which I should do more of anyway, I waste too much time here).

The hotness calculation seems to be pretty basic, just grabbing the points / comments numbers on the page and comparing them to each other. Which is actually exactly what I want, I'm not really interested in something which tells me exactly what HN's sorting equation tells me, and more complex == harder to understand the results.

Found a bug, btw: upvoting gives me NaN instead of a number for points.