With such an object - ContentObserver | Android Developers - it would be possible to catch events depending on new content, e. g. new emails.
Example: https://groups.google.com/forum/?hl=de&fromgroups#!topic/android-developers/6sBMKpnraBw (Posting from 28/11/2009)
Example: https://groups.google.com/forum/?hl=de&fromgroups#!topic/android-developers/6sBMKpnraBw (Posting from 28/11/2009)