We've supported RSS-to-email for almost a year now, and it's been a great way for folks to send out newsletters without having to write a single line of code or worry about copy+paste woes.

Some intrepid power-users have set up integrations that have multiple RSS feeds for a single newsletter (since you can also tailor certain RSS feeds to certain tags!), and it can be annoying to keep track of which URLs are which. So we added labels to RSS feeds! Hope that helps!