Rather than make a long list in legalese to try and confuse you, we're going to lay this out in simple terms for you, so you know exactly what we're doing and storing.
The data stored is only what we consider necesary for the site to function. Naturally, as well as posts, we store your email and a salted, hashed password in accordance with current best practices. Your IP address is also stored, as both a security measure, and in our server access logs which are cleared periodically.
We don't care about your personal data. We are not, will not, and never will sell it or use it for anything nefarious.
We will, however, run a few algorithms on it from time to time. This is so that when the recommended blogs feature is enabled, we can show you folks you might like.
Data may also be used for internal analytics to see how certain site features are doing. Typically, this will be anonymised - that is, you'll just show in our data as "a user". We won't be able to link the data used in these to your blog.