As I have already stated in another thread, I think the idea of your app is good and I got it straight away. I agree with most people here though that you could do with a better design and layout of the site. I think you should invest some time in this, no matter how daunting it might seem now.

That said, as long as the site works, I think you should unleash it right now to the public. Don't wait to get it perfect. Release it and carry on working to improve it - using feedback you get from users. Prepare to be very busy though and I would suggest a comprehensive FAQs/Glossary section before you launch. If you don't add one then you might get swamped and not have time to get on with your improvements. Also, I think the yellow highlight is too bright across the top of the homepage.

Finally, to aid comprehension, I suggest that you replace the text in the yellow highlight with: "Take notes (stickies) from any resource including books (both printed and online), videos, podcasts, and more. Share your stickies or keep them private. Learn from others." or similar.

All the best.