You may notice that the sorting on http://weblogs.asp.net isn't strictly chronological anymore. Scott wrote up a post that details why this is.
The short version is that there is now an algorithm (Digg inspired) that sorts the posts based on relevance. New posts start on the top but to stay on top the post follows a weighted algorithm based on age, comments, views, rating, etc.
We're using this on weblogs.asp.net now — if you've got feedback let us know!