This setting determines whether your members are allowed to
set their various member options.
By default, members are allowed set
options such as whether they want to receive a digest version of the mailing
list, whether to receive an acknowledgement when posting, and other things.
On an announcement list, these
member options often do not apply. For instance, if you are sending out one
announcement per week, it does not make sense for members to be able to set
their membership to receive a daily digest.
In such a case, you may want to
disable the member's ability to set their own options. The options will no
longer appear in the web interface for joining and "your settings",
and email commands to set them will be rejected.