We live in a world where businesses are starting to have data in two different places in the cloud and on premise. Having data in the cloud with Office 365 is brilliant as it allows for more employees to be mobile and for them to access data and files from anywhere and on any device. Then we have that legacy data that exists on premise, which businesses still rely on as many of their key systems are still on these systems and we can create these hybrid environments where we get the best of both worlds.
SharePoint / Office 365 is made up of various applications: intranet/extranet, document management, personal cloud storage, enterprise social networking, enterprise search, business intelligence, workflow management, enterprise application store.
At Cloud Fish we build solutions that interact with SharePoint / Office 365 and we also use it as a place to run applications from.
Building Apps on Office 365 should be like Lego not Meccano