As taken from the US Battle.Net SC2 forums.
StarCraft II Secrets of the Masters
Season 2 is coming, and it will bring with it a ladder wipe, but at the same time, each player's profile will be upgraded with new UI elements, including awesome new artwork which denotes a player's rank within their division, as well as a record of performance in prior seasons, improved detail pages that are more colorful and rewarding for top players, featured replays, and many more. Matchmaking rating will be preserved, so a single placement match will be all that it takes to find your place on the ladder once again. On top of all these new features, two new leagues will be introduced to highlight the top players in each region: the Master League, which places roughly the top 5% of Diamond players in their own league, and the Grandmaster League, a very special, elite league which is comprised of the top 200 players in each gameplay region, which will be visible to other players