This would be better if it was designed with the end user in mind from the get go and in full control of defining portals himself. (and by that I mean, if you take the example linked by omneity , I should be the one defining which "shopping cart" i'm sending the recipe ingredients to or which social app is triggered and what data am I sending it).
For some reason this also gives me some "Fuschia OS" vibes  or at least how Google would want to have this as standard on the web...
 - https://news.ycombinator.com/item?id=23688857
 - https://www.youtube.com/watch?v=Z7qGHgF1Pb4
They've already resulted in at least one same-origin policy bypass, lol.