We removed this from the app. Right now you can open maps that are shared through groups or exist under "My Content"
Why take away functionality?
We took this out at after the first or second release a couple years ago because we added an actual browsing experience to the app where you can find maps shared to you. Before that was added the only way to access a map was through the hyperlink. The hyperlink workflow had various issues across iOS and Android that were outside the apps control. There were issues across different versions of Android and through the various Android Skins(Blur, Sense, TouchWiz etc) and through all the different browsers and various email and messaging clients not recognizing the hyperlink that this was adding more confusion to the workflow instead of helping out the user.
I noticed in a different thread you asked about workflows where this would be useful. I have been putting together a work order system using AGO maps and apps, and we are using GeoEvent Processor to send notification emails.
Here is the workflow:
1) Field staff receive notification email regarding task assignment
2) Staff clicks link to open the work order in Collector (ideally we pass lat lon in the url and Collector zooms to the feature)
3) Staff completes the work and enters attribute data in Collector
It would be nice if Esri made it a goal to include basic functionality in all of their apps:
Basic feature editing
Basic attribute editing
Opening from URL's and passing location
There are too many one trick pony apps (I love them all), that fall short as soon as you need to do two basic functions.
The workflow you listed is something we are working on building with the ecosystem of ArcGIS mobile apps. Check out this video from the UC Plenary from this year and you can see Craig giving a demo which is similar to your workflow.
Check it out here:
We prefer to use the old ArcGIS 'green' app mainly because maps can still be opened using hyperlinks and all of our maps can be utilized in this single app.This lines up with the 'one trick pony' comment from Perry Clark.
If we followed ESRI's suggestions, our users would have to search for maps in both apps (Collector and Explorer) each time a certain map was needed. We would prefer to leave out complexity which adds no value for our users.
So the ability to hyperlink maps was removed from Collector but not from Explorer? I can only speak to the iOS versions of these apps.