I've been thinking lately about whether the permissions for this plugin offer any value. The plugin should be disabled for anonymous users, but for other users, what is the value of being able to grant the feature to some users, and not other users?
What use cases do people have for making use of the permissions? Would it be a problem to just drop the permissions from the plugin? The bookmarks feature seems to be pretty benign; I can't see the harm in providing it to everyone. Can anyone think of security holes that would be opened by dropping the permission? Dropping the permission would certainly simplify installation.
The BOOKMARK_MODIFY is not currently used, and I can't see how it could be useful even as features are added. Is there a use case for allowing users to view bookmarks, but not add them? The only use-case I think of is to provide users with a set of read-only bookmarks, but can anyone actually envision using a feature like that in practice?
An alternative to permissions would be to have a user preference, so that users not wanting the feature could disable it.
What brought this to mind again, and caused me to raise a ticket, was the thought of suggesting to include the feature in the Bloodhound project, and simplifying the installation in order to make that a more realistic possibility.