this freak offered to give me a blowjob in exchange for posting a comment on their profile. obviously I declined

What information e621 collects and why
Information from webserver logs

We collect the following information in webserver logs from every visitor:

The Internet Protocol (IP) address
The date and time of the request
The page that was requested
The browser user agent string

These items are collected to ensure the security of the service (see "legimitate interests" in the GDPR), and are deleted after 25 days to balance it with user privacy.
Information in cookies

Our cookies for any users of the service may contain this information:

The unique session token for the website
User preferences
One or more "flash" messages (temporary notifications of an action's success or failure, to be displayed at the top of the next page load and then deleted)

Additionally, cookies of users that are logged in will contain this information:

An encrypted authentication secret unique to the user to persist their login