I guess I was a bit cryptic above :) I thought about suggesting a global permission "comment" ... but I like your word ... "annotate" if we're going to generalize the notion of a global permission to add additional information to an object...
But why a child general_comments_create or general_ratings_create in that case? We want to get rid of needless child perms as much as we can. I guess in this case one could argue that we want greater granularity but then, given the global nature of the two packages (if we ever do a decent job of integration of these services with all content-producing packages) why not just have "comment" and "rate" as separate global permissions?
And perhaps "categorize", too?
It's fine of course for these packages to create the new perms, I'm just suggesting they be considered global.
Which is actually more or less what Jeff's proposing, I'm just rambling out loud :)
