None: No caching is enabled. This is the default setting.
Application: The userview page content is cached at the application level. This means that the same content is visible to all users. This scope is suitable for readonly content that is meant to be shared by everyone e.g. public HTML content, general forms, etc.
User: The userview page content is cached per user. This means that there is a copy of personlized personalized content stored for each user login. This scope is suitable for a user's private content where there is heavy processing required to display, and is acceptable for the content be slightly delayed e.g. custom datalist inbox, personalized forms, etc.
Note that content is cached only for GET requests. Whenever a POST request is received, the corresponding cache entry is cleared to reflect the latest update.