1 I wonder if you'll be able to run YOU ARE HERE on 'em.

2 Why terrified? Location-tracking? Cyber-ghosts? "Must-buy-shiny-new-gadget" impulse?

3 Minority Report has something that will show you what this will likely to entail.  Whatever you're looking at, you'll have commercial specifically generated to just you.  

4 While I hardly want to be bombarded with advertisements everywhere, advertisements specifically targeted would be a nice improvement.  Certainly better than walking past a speaker and having it blare out something like "David, buy our medicines and you can have.....".  Of course, "David, new videos for you!  Nekomimi ninja robot maids in their panties!" wouldn't be much better....

5 Actually, in the movie, I believe those ads were personal-only, using multiple directional emitters and interference waves to basically spot-beam both video and audio straight into the victim's eyes and ears with minimal disruption to passers-by, who were receiving their own "treatment".

That said, you can do the same thing a lot more easily if you can get people to put on a pair of glasses with earbuds and displays built in.

6 I can kind of see a use for this for things like navigation, shopping (make my list at home, then check off items as I look at the bar codes when I put them in my cart,  etc.  Hoever, I'll only consider this if they fit over my prescription glasses, and I have TOTAL control over what appears on the heads display.  If there's even one pop-up or ad, I will never buy them.

7

Well, as they say, if you get a service for free then you are the product being sold.

If it acted the way you describe, then you'd have to pay a subscription for the service.