Kip Tandoorisaid: I think it would help us alot if we would have the option to delete our posts and/or threads. I think that the words we write belong to ourselves and nobody else. It's embarrassing to read the old posts we made over a decade ago. Thank you for your understanding.
You do know you're posting on the internet right, so nothing is truly "personal".
So saying only you should know about your posts is lol at best.
Thus like said above and on all your other threads, this isn't possible.
As long as Jagex keeps this legacy forum software instead of discarding it with a newer one, we're stuck with whatever features it has unless Jagex invests man-hours to implement minor changes here and there.
I might well be wrong here but there's something at the back of my mind telling me that if you have your forum account permanently deleted by Jagex (at your request) then all posts and threads by you vanish (idk if that goes for posts by a user that are "quoted" by another users at any point).
It's quite a faff getting your account deleted and I can't swear that all trace of your existence goes with it but it might be worth researching.
Also, I don't know if any such posts/threads, once deleted, would still be able to be seen in some archived format or other.
And lastly I'm not sure if your actual playing account is deleted in the process. Probably is.
But really, why even worry about what you posted a decade ago. I doubt anyone is terribly interested.