So.... Basically Nexon is saying they want to donate money to charity: water, and they don't want to do it w/o announcing it... in a sense they're advertising it.
And... at the same time Nexon is also saying they want maplers to feel like they are a part of the donation Nexon makes since we're the ones that provide them the money to donate.
Hence, we are being a part of it by "donating" our time into the game. And what does it mean for Nexon if we do these quests? ...Well it basically shows that people are playing their games = profit in the long run. People slowly begin associating Nexon no longer as a big money guzzling company that steals from kids, but now we say, Nexon is a nice company that cares about people w/o water.