The original CelebDAQ worked this way - you bought shares and then a dividend was paid out at the end of the week based on the celebs exposure in the media during the week. That exposure was used to make a determination on how the share price was affected. As to how exactly they worked out how it changed the share price is anyones guess. Maybe they had a dedicated formula, mabe not. I guess only the original founders will know the answer to that question.
We are a little more "interactive" than that - the world has moved on a bit in the 8 years+ since the original CelebDAQ game and the prices of the stock change all the time. So whilst the stock rising or falling affects your own portfolio in it's own right, you also get a dividend payment at the end of each week, currently 6pm every Sunday based on how your stocks have performed over the past 7 days. Once that performance has been calculated, it's used to generate a payment to you based on the amount of the stock you have. So, if the stock does really well - you do really well, if the stock doesn't do anything - you'll get nothing. Simple really.
However, you need to bear in mind that the amount you will get is completely dependant on how long you have held them for. If it's less than 7 days then you will get a payment but it will be based on the number of days you've held them. More than 7 days and you get the full amount.
There are two things that will prevent you getting a dividend payment. The first is if the celeb doesn't increase in value in the current week and the second is if you bought the shares on dividend day - you need to have held them for at least 1 day to get "something".
Lastly you need to understand the dividend payment is based on you holding the stock at dividend payment time. If you don't own it when the payment is due to be made - you won't get anything. So, for example say you buy shares in a celeb on Monday and keep them all week until Friday when you sell them. During the week you were projected to get a dividend of 20K - but because you didn't have them when on Sunday (you sold them on Friday), you won't get that payment.