Stealth Mode allows you to browse other profiles on the site without letting them know you are interested. In Stealth Mode, the following features are enabled:

You will not be shown as "Online" to other users
Other users will not know when you view their profile
Other users will not know when you add them as a favorite

The drawback is that you will get fewer responses from other members in Stealth Mode because they won't know you are interested. We recommend against remaining in Stealth Mode for long periods of time as you will end up meeting less people as a result.