this relates to the news.yc source that was included with the arc2 source. Huge props to the YC people for putting this out there. I love just being able to look and learn from their own code.
I see that news.yc uses a ranking algorithm (news.arc source starting at line 186) that uses the age in hours of the votes to calculate the score. I find that very interesting because I once tried to determine a good algorithm for ranking things and ran into the same problem that news.yc has, for which they handle with the rerank-random function (line 237). Basically the problem is that stories' scores wont deprecate until another vote has been cast upon them.
Their comments explain:
"; If something rose high then stopped getting votes, its score would
; decline but it would stay near the top. Newly inserted stories would
; thus get stuck in front of it. I avoid this by regularly adjusting
; the rank of a random top story."
An alternative approach I considered was giving each item a base score based off number of days (for example) since a fixed point in the past (eg Jan 1, 1970) . That way each item will degrade relative to newer items without ever needing another vote, since newer items gain the advantage of a larger base score in the calculation.
Anyways, I just wanted to give huge props for the source to news.yc and being able to learn from the masters themselves.
Sorry, is this a post for news.yc or these forums???