It's pretty grand to participate in a world event in an MMORPG. It's one of those rare times when everyone in the game can cooperate to reach a common goal; it feels very epic, and makes you feel part of a greater cause. Not to mention that it's fun.

One World of Warcraft gamer, who might share the same sentiments, asked in the forums if Blizzard has any plans to continue holding world events in the future. Blizzard poster Bornakk replied soon after, saying that:

We do plan to continue doing them from time to time, yes. One is happening right now on Sunwell Isle even.

If you haven't done any of the Sunwell quests yet (where have you been?) you might want to try it out. Participating in the Sunwell Isle quests help to unlock more content and areas, thus you help in a larger, world-scale quest.

As for future world events afterwards, well, we'll probably see a lot of those happen once Wrath of the Lich King hits.