One of the things I liked about the commenting system here was that I could delete a comment whenever with no time limit. I'm pretty neurotic when it comes to commenting, and I liked having the freedom to delete comments whenever if I ever regretted posting them. Now it seems like there's a 4 minute time limit on deleting comments. So, why add it now? Not sure what the benefit could be. If it has to do with negative comments/trolling, wouldn't the mods delete those comments anyway? Never really understood why most sites limit it.
Edit: Also, it looks like they've added the option to delete forum threads you've started, which is an addition that makes sense (before you had to send a pm request to the mods).