In the following news in August 2022, I informed our community that almost 380,000 inactive user accounts had been deleted. See here:
https://www.psd-tutorials.de/threads/inaktive-userprofile-wurden-geloescht.189281/

As a forum operator, you always feel honored when you can boast a high number of users. But in our case, this no longer corresponds to reality.
Such deletions have often been carried out in the past because it makes sense to maintain and save data.

If I look at the ID of a newly registered user in July 2023, I see 830850. There were actually once that many registered user accounts on PSD-Tutorials.de. An impressive number. However, the portal statistics themselves show: 66,612 members. This shows that we have already deleted over 764,000 registered users in the past (most of them via such clean-up campaigns). There is also an SEO background to this. Every user account has at least two subpages in the profile, which are almost identical except for a few details such as name, date of registration, etc. From this perspective, we would otherwise have over 1.5 million subpages with very, very little quality, which can be perceived as duplicate content. In relation to 2.5 million forum posts, this would mean that this unqualified content would have reduced the overall relevance of all content . As a result, we were also able to strengthen the relevant content (forum posts) in relation to all subpages through this deletion action and thus support the overall relevance .

Another special feature, which mainly affects forums with user-generated content , are links to external pages and image content , which are also integrated via external links from image upload portals.

We were able to install an extension for Xenforo, our forum software, which automatically removes images in the forum that no longer work and were hosted on external servers. The script can be used to check the forum for links that are no longer valid and then either correct or remove them. A total of 580,000 invalid links were removed from the forum. Quite a lot, which should make the content a little more qualitative for Google (and the users), as a lot of inactive data garbage has been removed.

Tools for removing invalid links in the forum

Such tools are certainly also available for other CMS or forum systems. Alternatively, developers can also program such a tool themselves. If your project contains a lot of user-generated content (or your own content), use such tools to check the validity of links to external pages. Seobility also shows you all external links that have problems under Structure.