Review on Cayley by Ricardo Mercado

I like that it allows for you to easily query your data, even if you don't have all of the necessary information about the object at hand. It also has easy APIs for integration with other services (like Twitter). The documentation could be more thorough; there are some things that aren't clear from reading through the code itself. If you're looking for something that will allow you to store large amounts of structured data without having to write any custom software or databases, this may suit your needs. We were able to use Cayley as our primary source of data storage.