As per popular request I've updated My Threads to work a bit differently.
Here's how it works:
If you create a new thread, or reply to a thread, the thread is bookmarked in My Threads. The thread is not displayed since there has been no activity after you yet.
When somebody replies after your last reply, then the thread is shown in My Threads since it has had new acitvity.
If you read the thread again, it will once again not get displayed in My Threads since you have read the latest updates.
So basically, only threads that have been replied to after your last reply or read will be shown.
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