The fact that the rounded rectangle boxes are not evenly spaced shows lack of attention to detail. (yes I'm being a jerk here, but I've found that negative feedback from others has helped me make my project better)
The graphics are grainy. They should be stark and clean. There is too much use of two colors. It feels too monochromatic.
You need a better descriptions to communicate what benefit you have for people to join. Why should I join? There needs to be a more obvious "in your face" explanation highlighting something. The message should be along the lines of "If I join, then _______ is a possibility for me" - what I mean here is that this is the feeling that needs to be evoked within your visitors perception when they read one of the rounded boxes.
The graph could be a 3D graph, it will look unique and at the same time convey a hidden message to explore the site. It's a subtle message that if somebody sees an object of depth then they have an inclination to explore the site
On the about page, you need to have a margin on the sides. Feel free to make the font size bigger.
I click on the "about" section and have no clear way to get back to the main page - BIG MISTAKE! I see that there is an orange "return" button, but this is not intuitive. Clicking on the logo to take us back to the main page would be more intuitive for users and it will let people believe that this is easily navigable.