I love the innovative services coming out of the AWS teams. Snowball is a new addition to an old service.
Snowball is designed for customers that need to move lots of data (generally 10 terabytes or more) to AWS on a one-time or recurring basis. You simply request one or more from the AWS Management Console and wait a few days for the appliance to be delivered to your site. If you want to import a lot of data, you can order one or more Snowball appliances and run them in parallel.
As someone who has used AWS extensively in the past and took advantage of the Inport/Export service, Snowball is a huge step in making it easier for companies to migrate their data. Amazon does a great job describing what it was like to migrate large amounts of data in the past.
The original AWS Import/Export model was built around devices that you had to specify, purchase, maintain, format, package, ship, and track. While many AWS customers have used (and continue to use) this model, some challenges remain. For example, it does not make sense for you to buy multiple expensive devices as part of a one-time migration to AWS. In addition to data encryption requirements and device durability issues, creating the requisite manifest files for each device and each shipment adds additional overhead and leaves room for human error.
When I did this in the past, there felt like a lot of faith in the whole process. It worked, but with all the variables, a failure at any stage in the process would mean starting all over. Snowball is a great solution.