Open source bluetooth tags. Get close and they'll broadcast you a unique ID (for use with specific apps) or an url. And you can find out how far the tags are and select the closest of a set.
The idea seems neat at first. Bus stops and train platforms would broadcast an URL that gives you the current timetable for that specific route, and tags inside the vehicle could give you up to date info on the schedule, delays and so on.
For shops you could get to a section-specific inventory search screen - if you're at the nut-and-bolts section in the hardware store you click on the tag url to search for the particular size and type you need, and a small map showing where on the shelves it is.
Go to a restaurant and you have the menu and allergy info. Your suitcase can ping you as it comes down the arrival conveyor belt. Sets of tags will give you accurate navigation underground and dense, crowded spaces.
With just a bit more smarts (the link opens a bluetooth connection back to an embedded web server on the tag) your tires tell you how old they are and what the tire pressure is, plants tell you when they need watering, your appliances give you their status (is the laundry done yet) and service history.
Unfortunately, none of that will happen.
Here's the sentence that dooms this idea: "A beacon-equipped bus stop could send out transit times, stores could send promotions to the customers currently in the store, or a museum could send people information about the exhibit they're standing in front of."
The people that will be first and most enthusiastic about all this will be advertisers. It's a safe bet that if this ever starts taking off, 99% of tags will be for "promotional offers", discount coupons, deals of the day, Buy One Get One Free!!!
Bombarded with yet more advertising, people will uninstall or disable tag reader apps and stop clicking on the notifications. And since "nobody" uses them, serious uses of tags such as schedules - that need a fair bit of infrastructure investment - will never be deployed, leaving tags as yet another idea that could have been good but never was.