Between 1990 and 2010, the cost of one megabyte of disk storage went from $9 to $0.00015. Had the human population followed a similar growth, there would be 300 trillion people on Earth. (For simplicity, I am not taking inflation into account. It would make the result even more impressive.)
Between 1990 and 2010, the cost of one megabyte of RAM went from $110 to $0.01. With a similar growth in population, there would be 55 trillion people on Earth. (Again, I am not taking inflation into account.)
Many information systems have storage costs which are proportional to the number of individuals. I call them sapien-bound systems. They include most employee, customer and student databases. They also include blog engines and email systems. Soon, all sapien-bound systems will fit in RAM cheaply.