Managing a private wiki/LocalSettings.php/Default user options
See http://www.mediawiki.org/wiki/Manual:$wgDefaultUserOptions for the manual.
Changing watchlist settings
editA good way to help people stay involved is to set the default so that any page a user creates or edits gets added to their watchlist.
Add the following to LocalSettings:
$wgDefaultUserOptions ['watchcreations'] = true;
$wgDefaultUserOptions ['watchdefault'] = true;
$wgDefaultUserOptions ['watchmoves'] = true;
$wgDefaultUserOptions ['watchdeletion'] = true;
DPL alternative
editIf DPL is installed (and results are not cached), whole categories an be watched (useful when using subpages).