Before SL 1.2 was released, SL had a completely different resource allocation system. There were only 10,000 prims per sim, (as opposed to the current 15,000), and they were shared. In theory, all 10,000 prims could be put on a single 16 sq. m. plot of land. This led to what is known as the Tragedy of the Commons, where some residents took a larger share than what was deemed "fair" by the rest of the community, generating friction. This newfound scarcity led to what residents called "prim banks", where a resident would rez prims specifically so that others couldn't have them. This ensured that said residents would be able to expand their build in the future, by deleting those prims from the "bank".