A quick note for anyone writing documentation, or filling in default values in the configuration file for an application.
example.org are reserved for use in documentation. Thus, if you use
firstname.lastname@example.org in your default configuration file, you can be guaranteed that the address will never exist, and thus there will never be a "Bob" who is annoyed at your stupid choice of example domain names.
Addendum: The authority for this comes from RFC 2606, which also reserves the following top-level domains for the various, obvious uses: