Here is the note from their website:
Thank you to everyone who has donated snowflakes on behalf of the children of Sandy Hook Elementary School and the community of Newtown. We know that each snowflake represents the emotional outreach of the person making it. We have been overwhelmed by the outpouring of generosity from around not just the country but the world. At this time, we have enough beautiful snowflakes to blanket the community of Newtown. Therefore, with regret we must close the snowflake project to further donations. Please take this idea and your snowflakes and create a winter wonderland of your own in your community as a show of solidarity for our Newtown families. Please share your winter wonderlands with us. We would love to share your pictures with the families of Sandy Hook and all the other participating communities. Thank you for your heartfelt and amazing creations and for all of your magnificent notes and kind wishes for the Newtown community.