"Though the new feature is strangely undocumented by Apple, users have discovered that Mail now supports a system of URLs (yes, URLs can do more than point to porn) that allow you to link specific messages in other applications. For example, you could include links to a couple Mail messages from coworkers alongside notes, pictures, and web links in OmniOutliner or Yojimbo documents. This opens up a whole new productivity world, allowing you to bring your e-mail into other applications that aren't specifically designed to integrate with Leopard's Mail."
And it got me thinking about a post I wrote a while back about Facebook being how 'normal' people think email should work.
So, to revise my previous position slightly - I think it's becoming clear that we need some sort of hybrid protocol+action schema. I'm still of the opinion that these pseudo protocols are bad and detrimental in the long run and that it's better to deal with it now rather than deal with a schema-soup in the long run.