What does a red, parenthesized number mean.

- On the forums page, the column "Posts" shows the count of posts in "General Discussion", "On Writing Well", and "Hot Button Issues" always shows the number of posts in each forum.
- On the topics page, the column "Replies" shows a count of how many replies there have been to each topic.

Both of these columns sometimes show a red, parenthesized number after the count. What does that signify?