SOA takes advantage of SaaS and develops Applications as a service which run over those areas. 30% of the Fortune 2000 have some form of SOA in process. 90% of fortune 500 are well under way in development and deployment of SOA. Around 65% of 500 use some form of App Servers either from the Oracle or Old Leader BEA Systems. BEA Systems was the leader and was just purchased by Oracle. Now 70% of the entire world running Middleware use Oracle or BEA.
SOA leverages SaaS and is being used to develop Enterprise software. The reasons are Agility (ability to make quick changes to applications and business), Reuse of developed applications (referred to as services), intersection of SOA plus Event Driven Architecture (EDA) among other things enhances ROI. Once SOA is installed it reduces costs of new development by as much as 80%. The mantra for Business is flexibility, agility, reuse and then the addition of exceptional BPM and (BI) business Intelligence software added makes it inevitable that all fortune 2000 will make this transition.