AFAIR it follows E = mc^2, so even 5 grams will give you quite a boom.

Well, a black hole with the mass of an A4 page is gonna evaporate almost instantly, turning all of that mass into energy. Those 5 grams will give you about a 100 kT explosion.

That would earn them a percent of a percent of what they would through donations or running ads on their site. And they would be able to do it only once.