dr. dina miller, co-author of shrink wrap, three psychiatrists explain their work. thanks for both of you. iliana. 61,000 new installments, people installing it every single day. daily revenue of over $875,000. that's just in the united states. what makes this game so popular? >> i think it's a few things. i think it taps in a little bit to the nostalgia of acquainted, your childhood, that's something that's really appealing to people. every time you do something successfully on the game it gives you a nice little encourage you note, and that in itself is kind of spurring you on to keep playing. >> but it's also intellectually challenging. how does it make money? it sucks you into spending money. >> one of the brilliant things about the game, you have five lives to begin with and you have to wait 30 minutes to get another life. and it's only 30 cents to buy another life. you can find thatfully day when you are walk. >> 30 cents at a time it's making these enormous amounts of money.we compare it to blockbuster hoyle hollywood movies. diedinah, in a poll of candy crh