This is the number of new blogs created on a monthly basis.
This is the number of new users that WordPress.com receives. This varies from blogs because people might register just to comment or view a private blog, or get an Akismet API key.
We try to make it as easy to delete a blog as possible, as we try to discourage dead or zombie blogs, here’s how many users do that:
We gather a little bit of data when people delete a blog, about half the time it’s because they’re switching to a different URL on WordPress.com. Another quarter it’s because they’re switching to self-hosted WordPress, and the final quarter is people who are either not using their blog, decide to stop blogging for a variety of reasons, or they wanted features that aren’t available here.