@msz900, deleting those posts would only create problems. Firstly, the current activity of many users would be reduced and they could have problems with the rank they have right now, that could cause errors in the forum and it is possible (I'm not entirely sure) that many users will be demoted to lower ranks. It would also be chaos for SEO, since Google would have indexed thousands of posts that do not exist, and that always penalizes websites by showing links at the bottom. Furthermore, it would mean a huge workload, so I personally think it's better not to delete those posts.