I'm going to guess that your Google API parser is being rate limited thanks to the traffic volume you're seeing. Try adding some logging to that piece.

Also, you are running an outdated version of Rails that needs a security patch.

Great look for a first Rails project though, keep plugging away! Remember that most people aren't lucky enough to have popularity break their app ;)

Edit for code sample:

    Rails.logger.info " * Hitting Google now: #{your_google_parser.response.inspect}"

Redeploy, then:

   heroku logs -tail

Second edit for Google API advice:

From what I remember the GDATA APIs have not-entirely-documented rate limits. One naive solution I wrote in the past merely waited one second between sequential requests. This will obviously impact your app's responsiveness, so you'll want to figure out another strategy once you get it back up. Also, once you implement your rate limiting you still might have to wait ten minutes or so before Google lets you back in.