Mostly fact and maybe a little bit of opinion:
One of my pet peeves in programming is data interchange. I work exclusively with small business software (as opposed to working with corporate ERP systems) and I see that many small businesses store contacts two or three times in different types of software where there is little or no interchange. Time clock systems usually don't integrate with calendaring and project management systems. Task management may be in a system separate from project management, or more commonly, tasks are managed on paper or mentally. These are just a few examples of the data interchange problems I see every day in almost every small business.
It seems every software company has a different idea about how to store it's data and whether or not to expose that data for interchange and integration. If they do expose some of their data there is really no common standard to facilitate interchange or synchronization. You're always forced to read through the SDK/API documentation if you do want to program some type of integration and then it's almost never a painless experience to get it working and keep it working.
It would be really nice to receive an "electronic document" from our vendors that would allow us to quickly enter bills into our accounting system. It would be really nice if we hire a new employee that we could make one single entry somewhere, enter his roles and then he would be entered into all the correct systems even if his information would need to be flagged for review in systems such as accounting. It would be so nice if all our contacts were seamlessly shared between systems so that updating an address or phone number in one of them would make the changes in all of them.
Do data interchange standards for common entities such as people, purchase orders, sales orders/invoices, shipping documents, projects, tasks, appointments, etc. already exist?
Assuming some do exist, are they commonly accepted, ratified standards?
Would you program a business system to use or follow these standards if the initial requirements of the project did not call for it? In other words, how common or accepted are these standards, enough to be followed every time?