Another issue I detected today. This one is a particularly bad practice with regards to SEO and social media.
The slug name of a topic changes once the title changes.
That’s a big SEO no, no.
Imagine, you have a topic that has gained a lot of backlinks or is going viral on social media.
Now a TL3 user finds a typo in the title and changes the title.
The slug changes too and therefore the canonical URL.
All backlinks will be lost, and the topic will immediately stop going viral, as the former URL is now 404.
Slug names should freeze once a topic has been posted.
Only admins/mods should have the possibility to change the topic slugs and a warning should be given. Means, when I change the title as an admin/mod, options should be provided: only change the title, or change title and slug.
Update: I just found out that Discourse automatically 301 instead of 404 on slug changes. This mitigates the problem to some extend. Still would opt for a frozen slug.