I'm trying to get a mental handle on the 3 tiered DB app (DB-back end, Mid-tier, Web Server-Front end) and when it should be used in place of a smaller scale 2-tiered web app (DB-Backend, Web ...

Mobile clients could set a trend towards adoption of a new 2-tier application architecture that talks directly to a cloud-hosted database-as-a-service such as Database.com, cutting out the need ...