Short version: there is no account, no sign-up and no newsletter. You can read every page and use every tool without telling us anything.
The web server records what web servers record: the page requested, the time, a truncated IP address, the referring page and the browser string. Those lines are kept for a short window and used for two things, spotting abuse and seeing which lists people actually open. They are not sold and not handed to anyone except where the law requires it.
A list pasted into the checker is tested and then dropped. It is not written to disk, not queued and not added to anything published here. The only trace is a counter that enforces the daily allowance so one visitor cannot occupy the whole queue.
No advertising cookies and no cross-site trackers. A traffic counter records visits in aggregate so we can tell whether anyone reads this. Block it with any ad blocker and the site works exactly the same.
Some pages link to proxy providers, and those links carry a tag identifying this site as the source. It tells the provider where the visitor came from and nothing about who the visitor is. What happens after you arrive is covered by their policy, not this one.
None of the above is your real privacy risk here. Every address published on this site belongs to a stranger. Traffic through it passes through their machine and can be read and recorded by whoever runs it, and many are run precisely for that. A public proxy hides your address from the site you visit; it does not hide anything from the proxy.
So do not put a login, a payment, a private message or anything you would mind reading in public through a proxy from this site or any other free list. If a task needs to stay private, it needs a provider you have a contract with, whether that is a paid SOCKS5 plan or something else with a name attached. The lists on this site are for work where nobody is trusting anybody.
Requests about logs, or about an address of yours appearing in a list, go through the contact page. Background on how the lists are put together is on the about page.