Several months ago, we discussed something called Nearby, a project that - at the time - seemed to be Google's effort to let "people, places, and things" know when a user is, well, nearby. It seems that Google is still hard at work on its effort to connect various devices to each other and their surroundings, but Copresence (an internal name for this functionality) may have a more specific scope in this effort than we first estimated, apparently including iOS devices in the fun.
A couple of months ago, we posted one of our early Google Search/Now rumors, and it was something of a long range rumor compared to others. While things like parking reminders, proper timer management, and bill pay reminders have already seen their public release, the ability to set contact-based reminders ("remind me when I'm with this person"), hasn't come forward yet. But it will likely appear very soon with a new feature in Android called Nearby, which will allow new interactions between you and nearby people, places, and things.