iOS: Sometimes people remember when you’ve gone away, sometimes they don’t. If you want to make sure your friends know when you get back from your holiday (or any trip, for that matter), you can use IFTTT to take care of that automatically.
The IFTTT mobile app for iOS has a location-based channel that can automatically trigger events based on where you are. Once you leave your house, activate this recipe and it will post a status message of your choice (e.g. “I’m back!!!”) on Facebook. You could also make alternate versions of this recipe that notify people via email or other social networks like Twitter, but this pre-made version gives you a good starting point.