If you’ve ever wondered why healthcare institutions can’t easily share data between computer systems, just take a look at Calendaring in iOS, OS X, Outlook 2010 and Google Android/Chrome.
Google went down the road of calendar overlays. You can have as many calendars as you like and you can share them across a Google Apps domain or between Google users. Public calendars are available for subscription. My current Google Calendar calendar list holds twenty distinct calendars of which 8 belong to my family. (One for each family member, one for entire family, a couple of parent-only calendars that the kids don’t see.) In Google’s world, which is consistent across Chrome and Android, shared calendars can be read-only or read-write. Google supports invitations by messaging.
I love how Google does this, but I’m a geek.
I’ve not used any modern versions of Outlook, but Outlook 2010 also supported Calendar subscription. They didn’t do overlays though, every Calendar stood alone. I never found this very useful.
Apple did things differently. Not only differently from everyone else, but also differently between iOS, OS X, and iCloud. OS X supports calendar overlays and subscriptions, but the support of Google Calendar subscriptions is weird (there are two ways to view them and both are poorly documented). iOS has a very obscure calendar subscription feature that I suspect nobody has ever used, but it does support “family sharing” for up to 6 people/calendars (also barely documented). There’s an even more obscure way to see multiple overlay Google calendars on iOS, but really you should just buy Calendars 5.app.
iCloud’s web calendar view doesn’t have any UI support for Calendar sharing, I’ve not tested what it actually does. Apple is proof that a dysfunctional corporation can be insanely profitable.
All three corporations (four if you treat Apple as a split personality) more-or-less implement the (inevitably) quirky CalDAV standard and can share invitations. Of course Microsoft’s definition of “all-day” doesn’t match Apple or Google’s definition, and each implements unique calendar “fields” (attributes) that can’t be shared.
Google comes out of this looking pretty good — until you try to find documentation for your Android phone and its apps. Some kind of reference, like Google’s Android and Nexus user guides. As of Dec 2015 that link eventually leads to a lonely PDF published almost five years ago. That’s about it.
I don’t think modern IT’s productivity failure is a great mystery.