At today's Salesforce Developer Conference in Santa Clara, CEO Marc Benioff is announcing Salesforce SOA, a notable move on their part to deliver SOA, Service Oriented Architecture, as an external service on top of their Apex platform. Thus SOA meets SaaS (for more on SOA and SaaS trends see this timely piece by Dion Hinchcliffe).
In particular, Salesforce SOA builds on their enhancements from last year like Connect Out, our coverage here, by allowing a greater bi-directional, event-driven communication into and out of the Salesforce.com infrastructure. In a demo shown to me by Salesforce's Adam Gross, two independent browser windows were open, one pointing at an account record in Salesforce.com the other at a Google Spreadsheet. Changing values and clicking a submit in Salesforce caused the Google hosted spreadsheet to be updated almost instantly. In the past the Salesforce.com API allowed updates in the other direction, but now it's possible to integrate, SOA style, across systems in both directions.
This move by Salesforce.com is another step in the evolution of SaaS and web APIs to make the web as platform offer all the same services that used to be available only behind the corporate firewall. This will lead to a greater number of hybrid corporate IT applications consisting of a combination of internal IT systems and external web-based services.