Hmmm... maybe I'm doing something wrong, but somehow I can't get s9y to use a multi-site config as described on this page (by Garvin Hicking).
Of course, symlinking and such went fine and I get the config screen (serendipity_admin.php), but I miss the place where to change the database setup, which is done in the Debian package via db-config and lies in /etc/serendpity/database.inc.php.
This is my multisite setup so far (a mixed setup with copied/symlinked files):
lrwxrwxrwx archives -> /usr/share/serendipity/www/archives
lrwxrwxrwx bundled-libs -> /usr/share/serendipity/www/bundled-libs
lrwxrwxrwx comment.php -> /usr/share/serendipity/www/comment.php
lrwxrwxrwx exit.php -> /usr/share/serendipity/www/exit.php
lrwxrwxrwx include -> /usr/share/serendipity/www/include
lrwxrwxrwx index.php -> /usr/share/serendipity/www/index.php
lrwxrwxrwx lang -> /usr/share/serendipity/www/lang
lrwxrwxrwx plugins -> /usr/share/serendipity/www/plugins
lrwxrwxrwx rss.php -> /usr/share/serendipity/www/rss.php
-rw-r--r-- 1 serendipity_admin_image_selector.php
-rw-r--r-- 1 serendipity_admin.php
-rw-r--r-- 1 serendipity_config.inc.php
-rw-r--r-- 1 serendipity_config_local.inc.php
-rw-r--r-- 1 serendipity.css.php
lrwxrwxrwx wfwcomment.php -> /usr/share/serendipity/www/wfwcomment.php
Granted, during the last days I haven't found that much time (Easter holidays) yet to have a deeper look into the topic, but I got the impression that it's not that easy to use s9y on Debian with a shared installation setup as described on Garvins page. A sql scheme for the psql database is also missing in /usr/share/doc/serendipity.
Maybe you, dear lazyweb, have already a nice setup script for this purpose for Debian? Would be nice... :-)