Made a website to shop for college textbooks - need "next step" advice
As a weekend project to get into Node/Express/Websockets, I threw together a site that looks for cheaper places to buy your college textbooks: http://textbooksplease.com (click the "example" link for a demo if you're not in college).
Typical textbook expenses for college textbooks are between $1,000 and $1,500 per semester. You can usually cut over $800 off of that using my site.
I've made similar things in the past that only worked for my university (affiliate margins on textbooks are insane - it was a nice Summer job), but I was much more clever about it this time and it's now compatible with over 500 universities with little maintenance effort on my part.
So...what now? I launched and started publicizing it (facebook page/ads, adwords, some direct emails) about a week ago, and it's growing organically among my friends at my university (everyone I've shared it with has thanked me profusely), but I have a potential market of hundreds more universities I could potentially be marketing to.
What should I be doing that I'm not?
Technical/design/UX criticism is also extremely welcome.