Ask HN: Algorithm for ranking comments in a post

The other post mentions wilson confidence interval's. Here's the post I learned it from: http://www.evanmiller.org/how-not-to-sort-by-average-rating....

Thanks! Did I get these right?

- HN uses time decay to reduce score of older comments. While, Reddit uses wilson confidence interval to give provisional ranking for comments.

- Wilson confidence interval is useful when you want prospective score i.e. if comments are likely to get more upvotes in the future.

- For definitive score, (lets say, user played a game and has a score), HN's time decay will work better than wilson confidence interval?

Here is my current algorithm:

DiffInDays = Today - Date_1970_1_1; // Number of days between Today and Jan 1, 1970.

Rank = DiffInDays + (Score/1000); // Score is the equivalent of upvotes.

// Sort by Rank

You could create something based off reddit's http://amix.dk/blog/post/19588