Werner Vogels, the CTO of Amazon Web Services, gave  his annual “state of the cloud” presentation Wednesday morning at the GigaOm Structure 2011 conference in San Francisco. Vogels stated that Amazon’s S3 storage service doubled in volume from the same time last year and now houses 339 billion objects. Although Vogels still sees more potential for growth ahead mainly from enterprises building advanced applications, some using cloud-certified versions of applications from SAP and Oracle.

Vogel said Amazon’s spot pricing for AWS instances which allows customers to bid on unused Amazon EC2 capacity and run those instances when they meet defined price points, increased enterprise usage dramatically. Companies are able save money using spot pricing by running applications only when spot prices fall below a designated price point.

According to Vogel “This has become very, very successful in helping (web) architects feel comfortable about the prices they are paying. The things that are being enabled by spot pricing are amazing. Some of our customers have extremely sophisticated batch processing. Their bidding strategies are fascinating. They’re making sure they get the lowest price possible.”

Vogels said that spot pricing is now made available to Elastic MapReduce to encourage further adoption. MapReduce is a hosted Hadoop framework that offers AWS users the ability to process huge amounts of data.

Amazon cloud services are believed to be the most widely used,  Vogels noted that each day EC2 “infrastructure cloud” is spinning up enough virtual machines to run the equivalent of Amazon’s entire online retail operation circa 2000, when Amazon was a $2.78bn business.