I wrote in the comments of another post about this http://news.ycombinator.com/item?id=3484928. It was a bit off-topic so I'm expounding on it here.
I wish there was an app store for web apps. The web needs easy way to sell access to web apps like in the app store. If all I had to do was click 'purchase' and enter my password to get access to web apps like turntable.fm for a reasonable price, I would gladly pay. This would open up a whole new revenue model for web apps. There is a whole class of web apps that are trying to rely on ads now but don't have the millions of visitors a month to make that feasible. A web app store could provide a place for these lower traffic but still very useful and relevant products. I envy mobile developers since they have this avenue as an option. Who could pull this off? You need the database with everyones credit cards like Amazon or Paypal. Anyone else feel this way?
But yes, it exists: https://chrome.google.com/webstore/category/home