If someone contacts you and you're not interested in them, giving the silent treatment is okay. It might seem rude in the 'real world', but in the world of online dating, it's common
However, if you met someone in person after chatting online and the sparks didn't fly, it's rude to act like you never met the person. Keep the explanation short and sweet, something on the lines of: 'Sorry, I don't think we're a match'.
