It's courtesy to send a final message to the non-winning finalists or non-winning competitors to thank them for participating. This message should be sent at the same time the winners receive their award letters.
Thank you, again, for your submission to the <challenge name>.
While your submission was not selected as a winner, I want to acknowledge your effort as a participant in this crowdsourcing initiative. You created a submission that was well-crafted and engaging which made the selection process incredibly difficult for our team and the judging panel.
I am absolutely thrilled with the overwhelming response and quality of submissions. A wide variety of ideas from all over the world were submitted to solve our problem.
Thank you, again, for sharing your submission with us and we encourage you to take your ideas forward and turn them into a reality.