Interesting. A little weird site behaviour if you ask me. Does auto-bump when editing topics have any purpose? I understand that this is forum based around discussions, so bumping topics when there is a reply seems fair, but why would it bump the topic if you edit it a little? And can you for example edit your posts on purpose to always have your post on top, like putting extra space or changing one letter? I hope the site stops with auto-bumping after certain number of edits, otherwise this can be exploited in my opinion, especially that the site is now open.
I was thinking about situations where someone holds with creation of the topics until he has enough material to flood the front page. I didn’t realize that editing topics can bump them so it seemed to me that the purpose of this was to push other topics away to increase sales of the scripts. Still a reasonable limit won’t hurt anyone to prevent situations when someone will try to take advantage of how the site work to have his posts always on top over others.