The War Academy is the place where Strategy Guides (including guides about game mechanics, specific civs, etc.) will eventually go. While Strategy & Tips is the place for free-wheeling strategy discussions, the War Academy is intended to be more of a "library" of formal guides, allowing visitors to find those guides more easily than having to rely on search functions or manually rummaging in back pages of S&T. At this point, the number of strategy guides is small enough that stickying them in S&T works, but once the number of guides gets too large for the sticky route, we'll mass-move the guides to the War Academy.
To maintain some sense of order, only moderators can create threads in, or move threads to, the War Academy, but once guides are moved there, anyone will be able to reply to the threads, just as they can now in S&T. Future guides will still be able to be created in S&T and, once they are reasonably complete (guides aren't ever really "done," since future patches and expansions and other players' comments lead to changes/improvements to guides), can be moved by a moderator to the War Academy.