We went here with a Chinese friend on the first day of Chinese New Year. It was mega busy, and mega cold. The children looked like duvet's with heads and the river was not as thick as you would hope.
On the travel/culture informative side of things the incense is lit to bring 'goodluck' for the forth coming year, or the slogan that is everywhere a 'healthy and wealthy new year. I like this, straight to the point, no beating around the bush.