1. They'll use Incognito mode to surf the web without you ever knowing
It's fairly accepted these days that Google and Apple have changed the world as far as interaction with technology goes, providing a fairly-seamless transition should anyone decide to start getting into email or touch-screens. However the internet these days, rather like Star Wars' Mos Eisley, is just as worthy of being described as a "wretched hive of scum and villainy" as your average grimy estate or backstreet that you always tell your kids to stay away from. Apple however designed the first method of surfing the web without your history being stored back in 2005, and since then all the major web-browsers have followed suit, with Google even prompting you to be aware of "people standing behind you" when entering it's "Incognito" mode. Thus if you're leaving your ever-inquisitive and always-impressionable youngsters in front of a window to the world, chances are they're going to stumble upon this mode and go hog wild, discovering for every answer to a necessary life-question, a (totally intentional) deviation into looking at inappropriate content. Better keep an eye on things, and no, not those things! If you would like to share what your kids have gotten up to, or perhaps just your own stories of what you got up to and would like to reveal all, then feel free to populate the comments!
