The cost comes in the labor of the organization that needs to bootstrap and maintain the network of volunteers - this includes marketing to them that it's safe

The cost comes in the labor of the organization that needs to bootstrap and maintain the network of volunteers - this includes marketing to them that it's safe and worthwhile to load software onto their computer. For instance, SETI@home has a budget in the hundreds of thousands of dollars per year: http://setiathome.berkeley.edu/sah_budget.php http://setiathome.berkeley.edu/sah_budget.php . Who would donate to Snapchat@home when it's just as easy to get Snapchat+ads on your phone?