Despite my downtime, I was able to find the time to commit some changes I was having up my sleeve to the 1.1 beta version.
It involves, what many people have asked for: Specify, which user/usergroups are able to have access to certain plugins. My standpoint until now was, that plugins should implement the versatile permission management of Serendipity, available since version 0.9.
However, reality got me when I saw that no plugin was really ported yet to use that permission management setup to provide custom permission sets. But people wanted to have the ability to say "The staticpage plugin is only available to user XY".
Thus, I implemented a rather hackish way into the groupmanagement: You can now specify complete plugins, or specific event hooks which are forbidden for a usergroup. This way, you can say that group X is not allowed to execute a 'Staticpage' plugin.
This approach should work quite well for many usage scenarios - the upside is, that all old plugins are supported instantly. However, the neater approach of course is to modify plugins so that they provide their own permissions for more granulate control of what you want to achieve.
To enable this functionality you must first enable the option "Enable Plugin ACL for usergroups" in the serendipity configuration. The reason why you must explicitly enable this is, because those plugin checks decrease the performance of the plugin API. Every executed plugin hook must be checked against the blacklist, and those checks would hurt bloggers that do not intent to use this feature. To satisfy everyone, you have an option for this.
You can try the feature in the nightly builds created today, or using an SVN checkout. The feature is contained in 1.1-beta4.