> I interviewed with a stealth-level startup a few years back. They were developing a product, similar to a WiFi router, that would be installed on premise and sit there, filtering out Google/Facebook/etc. ads and replacing them with ads that the owner of the box wanted. You can imagine this box being installed in Starbucks, airports, libraries, and everywhere else.

Funny, I was a similar boat once. They weren't a startup, yet. Good for them, because in both meetings I had to tell them their business idea was impossible unless they broke prime factorization. I was surprised I had to meet them the second time.

Oh, and their business idea was a little more intrusive than merely replacing ads. They wanted to be able to read people's emails and Facebook data and serve targeted advertising based on that.