Threads are moved when they are posted in the wrong category. The easiest way to prevent this, is to look at the
forum index, and find the most appropriate area for your topic.
For example, if you post a new thread about your dog learning how to do magic tricks in the 67-72 message area, you should expect your thread to be moved. It would likely end up in the general discussion (off topic) area of the site.
Most times a redirect is left where you originally posted, so that you can find your thread.
If you click on the thread title, it will take you directly to your thread. You can then look at the top left of the screen and see what forum or sub forum it is now located in.