Although it may sound like a truism, the promotion of 10 days of applications to 10 cents has been a success for developers who participated (invited by Google). Any it may seem that it is logical, the lower the price more applications will be sold, but the question is that it has not only been a success of selling applications but money generated.
Although at the beginning it was thought that Google compensate developers paying them at original price, this has not been so. I.e. If an application passed cost 2.50 euros to 0.10 euros, the developer took each application sold 0.07 euros (must be deducted regardless of Google). The developers risked sell much but not earn money on it. However this has not happened.
Although they do not give specific numbers, there are some cases that we can learn. For example, Fieldrunner is sold at $2.99. That day went to $0.10 (U.S. promotion was in dollars). And therefore if sales multiplied by 30 that day, he went out to account. If it stayed below, they had won more money without making the promotion. But really sales multiplied by 70. That is, it was a very successful promotion.
Not to mention with the advertising that have received the applications that have participated. For example, the same as Fieldrunner indicate that application is sold twice after that before the promotion. I.e., they are earning much more money.
But which have not been able to participate in the promotion have been harmed by Google it is clear that those who were invited and accepted (was voluntary) have made a windfall. Sales on that day were very good, far surpassing previous earnings and now will have a time of superiors, received advertising sales. Will also need to see that they have gone up many jobs in the best-selling applications from the Market, that I consulted both Android users.