Google Forms data are stored in forms now - a new option

Announcement from Google - Features launching on June 11th, 2013

"Google Forms: Users now have access to a new version of Google Forms. Just as with Docs, Sheets and Slides, you can now collaborate with others in real-time. Multiple users can work on the same form simultaneously. Unlike the previous version, forms are no longer tied to a specific spreadsheet. Responses are collected and stored only in the form. If owners prefer to see the data in a spreadsheet, they can specify a destination spreadsheet for the data at any time."

Check it out further from their blog.