Most threads that are locked usually have corresponding "tags" to the left or right of the thread. For instance, your Modern Warfare 2 and 3 thread was locked for not adhering to the stickied Call of Duty thread at the top of the Video Games forum. Stickies are there to relay important information and/or keep very popular and general threads at the top (to prevent more duplicates).
Other popular tags include [ans] (answered), [dup] (duplicate), [req] (requested), and [resolved] (problem was fixed).
there probly locked because someones toled you the reason hope this helps! and what happens when someone spams and they get points and no moderators delete it?