The site tries to produce collaborative intelligence - a very interesting and upcoming field. It reminds me of the X PRIZE Foundation. However, in contrast to it, the competition aspect is missing.
For this reason the page has no real-life background and is not interesting for people with a scientific education which possibly could imagine to participate in a project that targets the solution of the mentioned problems. Those people can only be attracted, if they can share knowledge and gain knowledge and recognition of their knowledge. Other people that are not inventors, engineers, scientists or similar simply are overwhelmed by the kind of the problems. Maybe they even have interesting ideas in mind, but they will think that their idea might be incorrect, stupid or ridiculous.
I guess that you don't want to start a scientific platform, but rather a place for ,,everyday people''. Then you should simplify the way, people provide their solution. People that come across your page, usually
- have little time
- maybe have an idea in mind
- don't want and/or don't can elaborate much on their solution
I suggest you to just ask for one sentence, that describes their idea. List all of the ideas and allow the visitor to scroll down all ideas and to vote ideas up. Try to make it quick and fun. Pay attention to a very appealing design. The site can become a place to discuss about the proposed solutions, if comments (maybe in facebook-style) below the ideas are allowed. Maybe you or others will have even more ideas. I encourage you to continue your work!
The same applies to the problem descriptions: Try to shorten them as much as possible. The visitor should be able to realize without much reading what the problem is about. Try to use pictures, that visualize the problems. Summarizing, it should be entertaining to browse through the "problems"