This morning while I was browsing the forums via my table I noticed you have to do a lot of scrolling when looking at lists of threads in the forums. To make it a little easier on users when using mobile devices I've changed the default number of threads per page from 20 to 15.

 

This software does not have that option. I went looking on Xenforo's site to see if there was a way for users to set it individually, and this is what one of their developers said:

They mentioned it breaks links too, if one user links to page 3, it might actually be page 2 for another. Said you should set this once, and don't change it. So I set it back at 20 a couple minutes ago and that's where's it's gotta stay so I don't run into the issues they described.

 

Here's an example I've made up, to show how it causes issues, whether their link to a page, or a post, if individual users can change it:

User has his posts per page set to 40. He clicks the #postnumber link next to a post, so he can post that link a thread, directly to the post. All find and dandy, he gets this link:

www. site . com/threads/this-is-a-thread.655/page-2#post-5229

But everyone else, including Google, Bing, etc. sees posts via the global 20 posts per page setting. For them the correct link would be:
www. site . com/threads/this-is-a-thread.655/page-4#post-5229

But due to the post number at the end, Xenforo can find the correct page to display either way. Fine and dandy, that's what VBulletin does. And Vbulletin also destroys search engine ranking by allowing it. Why? Because when multiple URLs all point to the same content, the search engines see it as either (a) spam or (b) duplicate content.

So what the XF support team is saying is that they decided to avoid the user link issues, negative search engine issues, etc. but leaving the setting out for users completely.