Preview of a thread
On some other forums when the mouse is placed over a thread link in a forum a "tooltip" is brought up that shows the first couple of sentences of the first post in the thread. This is similar to what happens when you place the mouse over a smile glyph and a tooltip box comes up with the smile name.
Why add this feature? Many times the thread title does not accurately reflect the thread topic or what you might be searching for with in various threads.
Or in many cases the thread sounds interesting but in reality it is not and people waste time waiting for a thread to load to only immediately read two sentences and go back within the browser.