Trusted Contacts can reactively share your location, even if your phone is out of battery, when linked friends ping your account using the service. Alternatively, you can use it to proactively ping certain people and give a short status -- say, if you're walking home late at night -- and then turn it off when you get home safe.
Google's also added a few things to the Android version. The app now lets you toggle how long it'll wait before sending your location to contacts should you lose signal. If you go hiking in the mountains, you can toggle how long the app waits before automatically sharing your location -- assuming, say, you got lost and can't get signal. Android users can also add contacts by phone number or email, which is sent as a message that users can click through to connect to the app's service. Finally, nine new languages have been added to Trusted Contacts, including Greek, Persian and Urdu, bringing the total up to 25.