We have yet to properly document the feature, but you can now create forms that send emails to the address of your choosing. Some details on Pierre's blog.
Started prototyping a mailing list turning blog. Still very early days, and might not get anywhere. Again some details on Pierre's blog.
Also thinking of building a web-based (Monaco-powered), offline-first editor, so anyone can write HTML and CSS and start a site without any installs. Either directly from the admin UI, or possibly on another domain altogether. This requires the API surface for xmit download, which gives it a new sense of urgency.