What mechanisms exist to ensure the privacy of web application user data?
What mechanisms exist, if any, to protect a user's privacy and data for web applications? I ask because I would like to create one myself, and was wondering if there's any way of guaranteeing my users their privacy beyond my word that I wouldn't look in the database. I imagine big companies have complicated procedures and a way of locking down their data, but how does a single person, or a small startup do it?

By the way, I'm planning on using Google App Engine. I mention it in case that can offer a solution.
What mechanisms exist to ensure the privacy of web application user data?
===

What mechanisms exist, if any, to protect a user's privacy and data for web applications? I ask because I would like to create one myself, and was wondering if there's any way of guaranteeing my users their privacy beyond my word that I wouldn't look in the database. I imagine big companies have complicated procedures and a way of locking down their data, but how does a single person, or a small startup do it?

By the way, I'm planning on using Google App Engine. I mention it in case that can offer a solution.