Why don't my posts show up in the 'Most Popular Discussions' section at the top of the main page when they meet the criteria?

I had a post yanked from the top of the 'by number of comments' box on July 16th. Since then none of my posts have been on either side of the 'Most Popular Discussions' box. Why?

I have never recieved an explanation for being barred from the 'comments' section. Could I get that, or just reinstated?