When our machines talk to one another behind our back

What do toys do when children go to sleep? These days your childhood fears get a legitimate incarnation when your grown-up toys -- gadgets, apps, software programs -- start talking to one another behind your back. Case in point:

One woman went on vacation, leaving an email auto-responder reply to her emails. Somehow it found a way into Facebook, as a comment on a post. Clearly, the auto-responder replied to a notification from Facebook, but it's kind of headscratching what exactly it responded to. I don't see that this woman had previously commented on this post, so why did she get a notification about it? Well, maybe the author of the photo tagged her in this photo (as some clueless people do to make sure that their friends really, really look at their pictures). That would explain it. Oh, the fun our machines have when we're not around.