I usually click on "show unread posts since last visit" to read what has been posted since my last visit. Recently I had read all posts that indicated they were new, and decided to click on the message "No unread topics found since your last visit. Click here to try all unread topics. " Lo and behold, i discovered a list of new topics that I had not read. So if you want to make sure you do not miss something, click on the unread topics after you have read all the new posts, and you will see the new topics as well as the new posts in topics you have already looked at.
I've also discovered if you click on the topic heading, it will take you to the topic, but if you click on the actual word "new" it will take you to the exact page and place where you read the last message.