Before Wrath of the Lich King, World PvP was a pretty straightforward aspect of Warcraft. There were a handful of objectives in Outland that allowed players to do a couple of very simple tasks like retaking Haala or killing their opponents and taking the towers or beacons in Zangarmarsh, Hellfire or Terokkar Forest. The objectives were easy but no one really did them because the reward was minimal and was often zone-wide so everyone got it. There had been no reason to take part if 12 other players did it for you once every hour or two.
But all that changed when WotLK hit and the game started emphasising more complicated, realtime battles in World PvP with their first real time PvP battle sector in Lake Wintergrasp. The new section had players facing off in classic battles on the live server ( no instancing ) and getting rewarded with points that would let them buy rare and valuable items like the new Heirloom items that may be used on any personality in the account from level one to eighty and beyond.
In addition to the way in which the game now works on live servers, many players can get without delay concerned to incorporate a slew of different ways that players can use weaknesses of their opponents, use PvP to get into PvE content and then get rewarded with everything from Emblems of Heroism to the rare and valuable Season 5 Gear.
In the end, whilst there are new PvP objectives and World PvP options in Grizzly Hills as well, you are only going to hear about Lake Wintergrasp where Blizzard has put into place options than ever before to get players concerned, make sure that the content remains fresh and topical and to build up a means by which they can grow their PvP options to struggle against other MMOs built completely on PvP like Warhammer Online.
World PvP is here for good and as the recognition of Lake Wintergrasp dicates, you should expect a complete slew of new options in future patches and expansions as the game gets more depth added to real world PvP. Expect that your ability level now will have a big effect on how you perform in the future as well, particularly if you would like to start to get the top rewards and accomplishments.