The following is an excerpt from a post at the Language Log Blog, by noted Sinologist Victor Mair. The full post my be read here.
Two years ago, the favored lunar New Year's greeting in China was "Happy 牛 Year!" where 牛 ("bovine") is pronounced niú in Mandarin and is standing in for "New" in the Year of the Ox / Bull / Cow.
Last year, the Year of the Tiger, "I 老虎 U", where lǎohǔ 老虎 (which means "tiger") sounds like "love" to some Chinese speakers, was conveniently and concurrently being used to celebrate the New Year, Valentine's Day, and a famous golfer's amorous escapades.
Well, this is the year of the rabbit, so you can be sure the Chinese would come up with a clever way to incorporate their word for rabbit (or hare) in this year's favored New Year's greeting, and indeed they have.
What we have for the current year is "Happy New Year 兔 you", where tù 兔 ("rabbit, hare") is standing in for English "to," hence "Happy New Year to You!"
This clever New Year's greeting, which is already flying around the Chinese cybersphere, seems to have won out over two other less catchy attempts to incorporate a bunny wabbit into the mandatory New Year's Sino-English salutation.