By default, your newsletter has a public-facing archive on the web, which you can visit at either your custom domain or at https://buttondown.com/username, where username corresponds to the username that you've set in Settings → Basics.
You can view all of your archives's settings, including the ability to turn them off, at Settings → Archives. For more on customizing your archives, go to Designing your archives.
Buttondown automatically indexes the following content of yours in Bing and Google:
Buttondown respects canonical URLs; if your emails are being created through an RSS feed, for instance, we'll point Google (or whoever) to the original URL of your content to make sure the SEO gods are checking in the right place.
If you've got archives turned on for your newsletter, you still might want to 'hide' certain emails from the archive. This could be for a variety of reasons, such as:
Whatever the reason, you can exclude emails from the archive both as you send the email and after you've sent it, by setting the email as private. Private emails:
When you're sending an email, you can set it as private by opening the "Recipients" modal and choosing "Private":
If you've already sent an email and you want to make it private, you can do so by going into the Emails list page, clicking the dropdown menu, and selecting "Change visibility":