Google adsense keeps denying my app from having ads, because of an "insufficient content" issue.

I manage a Web Application that allows the users to set Youtube Videos as Alarm Clocks. It includes an in-site Youtube search to retrieve videos from user queries and lists the users alarms.

The site has a good traffic (500 users per day), is currently promoted by Google in Google Chrome Webstore, and the ajax requests are crawlable, following Google's guidelines (https://developers.google.com/webmasters/ajax-crawling/).

Although I understand there is not much content, beyond the user-generated, I really don't what else should I include in the site. Perhaps adding contact and about pages, and maybe another section would increase the navigation. Google argues I need a "fully launched and functioning site, allowing users to navigate throughout your site with a menu, sitemap, or appropiate links". They also ask for "full sentences or paragraphs"

Isn't a Google Adsense solutions for Web Applications? Would all the web-apps have to include useless navigable subpages?