If it was not new user adoption, you'd think they rather shut the fuck up though, wouldn't you?
"Dear XXX
Thank you for your patience and support all throughout 2013.
As we noted in our previous update there are many things happening, and we’re proud to announce two more major developments that will make MtGox both easier and more economical for our valued customers:
1) One million MtGox customers and reduced fees for the holidays!
Thanks to our loyal customer and increased global interest in Bitcoin, MtGox has now achieved a milestone of over one million customers and growing. This is an incredible moment for us all, and to celebrate, we are offering a Special Holiday Discount of 25% off all trading fees starting today, December 20th 2013 to January 20th 2014!
....
"