Allow some comments to be used on all sites

[501st-alpha1]

While many of my auto-comments are site-specific, there is a not-insignificant set of comments that are the same no matter the site. As I understand it, the comments are currently stored in site-specific local storage, so I must manually copy/paste such comments across any sites that I want to use them on.

I'd like to request that an option be added to persist some auto comments across all StackExchange sites. This StackOverflow post indicates that it should be possible to store cross-domain data with Greasemonkey.

If this is implemented, then I would prefer the import/export screen to show all comments, indicating whether they are cross-site or for a specific site.