Hello,
Your code is okay as long as it works. Don't worry about scalability now. Once your site hits the threshold where you see the website hitting its bottleneck, you can then do improvements or re-do everything in a different language. Every huge site starts with terrible code and then gets improved. Don't worry about it now. No matter how optimized it will be now, it has to be improved and optimized further when it has to be scaled.
The problem I see though is the design. There's design flaws. Two signups in the same page. Thumbnail is gets distorted with the left navigation panel. We have to redesign it. It's like advertising, no matter how good the product is, you have to impress the people to try it. We have to make it to look good because we don't have pre-promotions, pre-audience, etc. I can redesign it for you and if you still want to improve your code, I can do that too. I didn't see the bid and all, I just want to tell you want I wanted to. I couldn't find direct message here.
Hope you read this. Thank you.