When you click the last post icon the system should take you to the post that it registers as the newest post that you haven't read in the thread. If you're having a problem with that working try this
http://www.cybertron.ca/boards/forum...hp?do=markread to mark all threads as read.
The latest threads column on the front page will not have that option because if it were to be added in the Latest Threads sidebar would take up the entire navbar with all the additional information that would need to be listed as part of it. If you want to see all the latest posts try the New Posts link at the top.
Thanks.