I think you could increase the usage of your site dramatically if you featured a simple, single example of a use case on your homepage which highlights the sites benefits.
E.g. if I search for a particular camera brand, how will your site be a better experience (for me as a user) than simply doing the same search through Google without using your site?
Currently, it's not possible to see the benefits, features or example usages of the site without first going through a sign-up process.
I'd make these small improvements and seeing any effects before deciding to move on.