This page describes some of the technology underlying the Where app. There are a couple of interesting design choices.
In general, Where does not need to know the identity of the user. Most users can find their services without identifying themselves. There are two exceptions:
Users can identify themselves using their Google or Facebook IDs, or create an new accounts using their email or Mobile phone number. They email or phone number is not recorded by Where. It is used to create a unique account ID.
As mentioned above, Where does not store the user's name, phone number or email address in its data bases. It uses the Google authentication service to validate users. This means that user's identity and other information will not be compromised if the Where database is ever hacked. Further, publicizing that there is no hacker worthy information in the database should reduce the temptation for people to mess with it.
The information currently stored in the database is limited to: