In the blog post it said this.

Coming Soon: Build New York !

The Big Apple is coming to Sanrio Land and you can help to build it! Players who participate in this momentous in-game event will have a chance to be immortalized in Hello Kitty Online’s super-cute version of the city that never sleeps, New York ! Stay tuned for more details. Warning: this event is imminent! Do not miss it!

So how do you build New York inside Hello Kitty Online?