Preferences affect a user's experience with the program.

Search results per page
For example, you can control how many results or private messages will be displayed on a page or prevent pagination altogether by selecting All

List name format
List name format essentially determines how all names in the program are displayed and are generally a matter of personal taste. Last First is powerful because of the alphabetization. A user can just start typing in someone's last name and it will skip to that person.

E-mail on new private message
E-mail on new PM will inform a user via e-mail when they have received a new message, in case they check iWebPress infrequently.

Time zone
Setting the appropriate time zone is of course important so that times make sense to the user. All times are relative to Greenwich Mean Time (GMT), also known as Coordinated Universal Time/Temps Universel Coordonné (UTC) or Zulu time. If you are not sure of your proper offset, click on the globe to the right to get the location.

E-mail format
Finally, if you use a use old webmail clients that don't properly render html formatted e-mail, you may wish to receive plain-text only.

The defaults for most of these options can be found in the advanced site configuration panel (See Site Preferences in the Admin section).