A JQL function to search by the number of comments would be useful in a number of situations:

1. You could look for tickets with a low amount of interaction.
   1. In support, we might use this to find cases where the customer never got back to us so we can phone them.
   2. In development, you might use this to search for older issues that are still awaiting a comment from the development team.
2. You could look for tickets with a high amount of interaction.
   1. In a development context, this might be another measure of issue popularity.
   2. In a support context, you would want to add as much value as you can in the first interaction, and could review cases that required more than N bounces to resolve.
   3. In any context, this could be used to look for trends or flame wars that need review.

Filtering by who the comments are made by (especially by groups) would be helpful, as would filtering for comments made by assignee or reporter. As an example, I could search for:

1. Issues where there are no comments by anyone other than the reporter, for example, to help find cases that have had no meaningful response.
2. Popular issues where there are no comments by the company.

The last example would be improved if you could also filter for the number of comments in a particular date range. Imagine being able to look for issues with a huge number of comments in the last month that have no comment from the developers.