I recently started a new website http://www.BigBigLens.com. I want it to be an open platform for users to register to post and share the photos. I categorise the photos by the lens used to take them. Up to now, I only have a couple of good friends putting their photos there. How can I get more users to register and share? I have already made it easier to register - direct login via facebook. Your advice is important to me. Thank you.