Threads don’t disappear. Instead, the following factors are at play:
a) As the member above mentioned, when you enter a forum, by default, the thread list is sorted by a thread’s last post date. So, threads that have not received posts recently naturally get pushed further down the list.
b) By default, the thread list only displays threads which have received posts from the last week.
c) The Off Topic forum receives a high volume of spam. Like any other post, a spam post bumps a thread to the top of the list. However, spam posts are deleted by moderators. If the spam post is removed before another post is subsequently added to the thread, the thread goes back to wherever the last prior legitimate post causes it to be sorted. This phenomenon may give the appearance of threads coming and going from the list seemingly at random.
It is possible to change the default timeframe over which to include posts using your control panel:
https://bimmerpost.com/forums/profil...do=editoptions
You can use the “Default Thread Age Cut Off” to see more or fewer posts in the list. You can also change this and other options on a “one-time” basis using the controls at the bottom left in any forum’s thread list page. And you can even change the sort (for just the threads currently displayed per your date cut off) by clicking on the column headings in the thread list.
Finally, as also mentioned above, you can locate any thread by searching. I tend to use Google to search the forum because I like the flexibility. You can add a term to the search to limit results to Bimmerpost. Here’s an example
https://www.google.com/search?q=site:bimmerpost.com+bbq
If you need to search based on parameters that are specific to the forum, such as filtering by a user, the forum’s native search function can sometimes be the better choice.