Hey, a few suggestions from my side.
I like your concept (your concept behind the website) but you will have to keep in mind that this can be a success story if you know how to target your audience. I am talking from a visitors point of view. I think you should in a way focus on the points that I am listing below.
1. Website should be desirable. I am talking about the look and feel of the website, therefore you should have a very desiring landing or homepage. This homepage should talk about your concept as well as it should have some pictures. The website should have a nice color scheme/theme to it. The only color you have used is green, add a couple of more colors.
2. Your categories(trending tags) should have icons. For example- Photography can have a small camera icon. There are different website from where you can get these icons or else you can design it by yourself. http://www.iconfinder.com is one such website from where you can get good icons.
3. You can have a better hover effect on the Sign Up and Sign In button.
That’s all for now.
All the very best!!!