My grand-daughter loves it. I haven't started her little brother on it yet, but will soon. She is 6 now and he is 2.
My nephew loves it. I have it bookmarked and he can click it himself to play games, feed his fish and hamsters there.
He's 3 1/2. It really has helped his computer skills too. He can work the mouse, before he would say "you do it"....he's learning to look for letters on the keyboard instead of pointing to them on the screen....he knows how to refresh the page if something doesn't load properly.