It's worth noting that this Just Works in Android due to intents.

I was a bit unclear. I wasn't complaining that the Google+ app could not somehow intercept my attempt to open a Google+ URL.

My complaint is that I had copied the URL, and wanted to paste it into the Google+ app, and have it display the content. That is something under the control of the app.

Sorry, but any requirement of the form "copy X and paste it into Y" cannot reasonably be considered as a "required to be a serious contender" feature for a mobile OS. Only the most serious of users have any clue how to do editing at the level of clipboard functionality.

And regardless: can you do that with Facebook app? I don't see how with the Android app in front of me.

The Google+ app isn't a browser. There's no reason you should expect to be able to cut and paste an arbitrary URL into it (except for posting, of course). What should the app do if you decided to paste: "http://www.cnn.com/ or whatever?

To me, Android's Intent setup is beautiful because the apps themselves decide whether they can or can't handle particular URLs (so Google+ can catch Google+ URLs, Twitter clients can catch Twitter URLs, Google Maps can (and other mapping providers could, for that matter) catch map/location URLs, etc.).

Without the right kind of extensible framework, I just don't see how you could do anything similar and usable in iOS.

No reason not to have a javascript redirect on the G+ page before rendering to ask if you want to go to the app, and then redirect to googleplus://

Nice workaround, but what to do about the browser's rendering? When the user goes back to the browser, what would he see?