I think this is sensible. I've changed the code to only include articles and comments from the last 30 days. (The side box may not update immediately as your browser is likely to do some caching.)
Thank you again. Karma Delta is a very neat new feature to play with, and it's making me smile to see the new "Top Contributors, 30 Days" :)
Is the karma shown that accumulated from posts and comments that were made within the past 30 days, or from all votes on all posts within the past 30 days, regardless of the age of the post or comment?