What is Mashery?

In the Amazon Services architecture article the podcast mentions Mashery. I went to their site at http://www.mashery.com/, but I can't quite figure out what it is.  They want to:

Unleash and manage channels for your API responsibly with Mashery’s combination of security, usage, access management, tracking, metrics, commerce, performance optimization and developer community tools.

An example would help, because I am not getting it.