I'd be interested to know if Google Now can do people reminders. Unfortunately I sold my last Android device so I'm unable to test it myself, but a quick search brings up this article[1] which suggests that it doesn't exist yet. Either way, I'm sure it's only a matter of time until both Siri and Google Now can do it too (which is a good thing, I've found it incredibly useful).
It can't do reminders when you are around people yet but there have been clues[1] that it's coming found when poking inside the Google Search app. It's expected to make use of the leaked Google Nearby[2] which will "...periodically turn on the mic, Wi-Fi, Bluetooth, and similar features..." to aid with proximity.
