We need a search engine for holographic layer services. It would be like Google, but for MR experiences. Holographic services would use a protocol that defines a geofence to be discovered by the layer search engine's crawler over the internet (this could just be a meta tag on a classic website). The HoloLens or whatever MR device would continuously ping the search engine with its location, and the results would be ordered based on their relevance (size of geofence and proximity are good indicators). The MR device would then show the most relevant available layer in the corner of the FOV. Selecting the layer would allow enabling it either once or always, and the device would then deliver the holographic layer over the internet. The holographic layer would behave like a web service worker (in fact, it could be a web service worker) and would augment a shared experience which contains other active holographic layers. For example, your Google Maps holographic layer could be providing you with a path to walk to the nearest Starbucks, and once you're outside Starbucks, the Starbucks layer is also activated, which allows you to place an order.
This concept of activated layers, I think, is a great way to avoid a future where we're being bombarded with augmented signage and unwanted experiences. In fact, you could go further and enable blocking notifications about specific/certain types of available services. (ie. don't notify me about bars or fast food restaurants.)