Every now and again somebody asks us moderators to delete old material, and we usually don't. Not that we can't. After all, we suffer spam and delete several such posts daily.
Why not?
Anybody posting on the net should work on the assumption that once it has been posted, it is there for ever. If you can see it for more than a few hours, a web crawler will have found it and cached the page in some archive or other. So removing an old post will not remove it from sight at all; anybody with a little savvy can find it easily.
Another thing is that this forum is a resource for learners. We ask people to
search, and the first place to search is
here. Removing old material reduces the scope for searching and reduces the value of this website.
Some people have the genuine fear that their work will be copied, and ask for removal for that reason. Actually, having the work visible with a name on is the best defence against copying. Not because nobody will copy it, but because anti‑plagiarism software will find the original work very quickly and the plagiarist will receive a mark of 0, or maybe even suffer a worse fate.
Some people may be scared that beginners'‑style posts may be an embarrassment when they apply for jobs. I am sure that potential employers know when their applicants started programming and would expect them to post beginner‑y posts then. And such embarrassment can be avoided by changing one's display name.
We have an
FAQ about this topic, which might be helpful.
[edited to fix link]