From the announcement:
We've got Spring Fever - and you get to benefit from it!!
In appreciation for everyone's support, everything is discounted 10% off on our website!! This includes all Miniature Building Authority and Direct Items. The discount will be taken off of the bottom of your order - no need to enter any codes. This sale will run from now until May 31st, 2012.
This sale can not be combined with other discounts.
(note this sale is not open to retail and distribution customers)