There are days when it all just comes together, and today is such a day for cloud computing. Amid AWS announcing PCI compliance, the release of Database.com and Rackspace’s new offerings, the running theme is that barriers are falling. Security, compliance, choice, public-versus-private — no longer are these insurmountable obstacles. But don’t think for a second that announcements like these are anything more than the tip of the iceberg. In the year to come, we’ll see all of these areas evolve in ways that will render yesterday’s cloud discussions irrelevant.