Short version: no accounts, no cookies, no email address asked for. Here is the long version.
When you lock in your ten, the site stores: the ten song ids in your order, your score against the masses at that moment, the prize you picked, the first name you typed if you typed one, a random token your browser made so you can only vote once, and a scrambled version of your connection's address. The scramble is a salted hash with a secret only the server holds, it is only ever compared to itself to stop scripts stuffing the ballot, and it is deleted after 24 hours by a scheduled job. The day you voted is kept.
Your ten is public by link. The card you share carries a link, and anyone who opens it sees your ten, the first name you typed, your prize and the day. That is the point of the card. Type no name and it says "a mate's ten".
That is all. There is nothing that identifies you, which is why there is no account to delete. If you typed your real name on the card and want it gone, email hello@definitelyten.com with the name and roughly when you voted.
Only your first lock-in counts as a vote. If it did not get through first time, that same first ten is sent when it does. Trying again is scored in your browser and never sent anywhere.
The site counts page views and the four steps of the game (started picking, locked in, chose a prize, shared) using PostHog, hosted in the EU. It runs in cookieless mode: nothing is written to your device, your address is discarded on arrival, there is no recording of what you do on the page, and you are never identified. That is why there is no cookie banner. Fonts and images are served from this site, so PostHog is the only other company in the picture.
Your picks, your order and your score are kept in your browser's local storage so you can come back to them. Clear the site's data and they are gone from your phone; the one vote described above is the only thing kept on ours.
An individual fan in the UK. An unofficial fan site, not affiliated with, endorsed by or connected to Oasis, their management or their label. Questions to the address above.