Correct, anyone whose preferences match yours would be able to find your nüurdle if they knew where and when to search for it. They can of course then also create a response but the way nüurdle works is that they also have to provide a description of you or describe the event. Let's take an example; you are at a cafe and there's a nice guy sipping his cappucino on the table opposite you, the two of you exchange glances and smiles a few times, you think wow but neither of you seem to have the courage to go and say hi. Enter nüurdle! You create a nüurdle and describe this guy (black hair, glasses, red jumper reading The Economist in Cafe Doodle). Now, your interesting guy would be able to search nüurdle as he knows the date and time when he encountered you, he'll then create a response with a description of you. You'll get that response in which you'll read a description of yourself and the encounter, so you accept and start chatting. Now imagine you receive a response that says something very generic or vague like "I saw you there and liked you", it's down to you but maybe this is not your mystery guy so you can ignore or reject. Similarly if the response says something completely wrong very clearly you just reject this response.