You hand in a few facts. The pool keeps them. A buyer can then ask a question that needs many people at once, such as how many, and your own row is never handed over.
Asking is not switched on yet: today this page is the hand-in. The asking side runs in the pool's own code, under the same rule, five people or more or no answer.
Your answers sit in a plain database. Nobody should tell you otherwise.
What protects you is the floor. The pool answers only about groups of five or more people. A question about a smaller group is refused outright.
Every number the pool gives out is fuzzy and rounded, and the size of the group behind it is rounded the same way. A buyer cannot use the pool as a ruler to count you.
Only the fields below are kept. Everything else is refused before it is stored.
When you hand in, you get a number. That number is how you pull an answer out of the pool. Paste it here with the field you want to withdraw.
Reading the pool.