I met somebody for the first time two days ago and the next day he sent a message on Facebook in which he said, "Thank you" and I replied "You're welcome! It was pleasure to meet you." Although it is a very simple construction, I've become confused after research I've done and because I will probably use it very often in the future, I would like to ask which one is more appropriate for this situation, and is there any difference in terms of meaning they suggest?
And as far as I know we can also say:
It was a pleasure to have met you.
But besides that, it is used in more formal writing? I have also read: "Do not use 'have met' unless they were your host and you are writing a thank you note." Is this correct?