Every time I open a thread to make a post, or read newly added posts, the 'hit count' is incremented by one.

Say a thread continued for 10 days and new posts were made every day. If I opened the thread to read the new posts once a day, the hit count would be incremented by 10.

Say there were 50 posts made and I opened the thread to read every new post as soon as it was made, then the hit count would be incremented by 50.

Say I was fixated on a thread, and I opened it 100 times to read and reread the posts, then the hit count would be incremented by 100.

Say I wanted to draw attention to a post and make it look like it was hot, then I could repeatedly open and close the thread to increment the hit count.