For distributed systems key value stores are the infrastructure that runs a lot of the larger companies like Facebook, Yahoo, Google, Reddit, etc. Facebook is

For distributed systems key value stores are the infrastructure that runs a lot of the larger companies like Facebook, Yahoo, Google, Reddit, etc. Facebook is famous for cassandra for example. They are tons of uses for them. A lot of them are evented and stored data analysis. People create new ones because performance is even more necessary if your business runs on these things for many services.