The Free Software Foundation is no longer at 675 Mass Ave, Cambridge, MA.
Our new address is 51 Franklin Street, Suite 500, Boston, MA 02110.
You can confirm this for yourself here: http://www.fsf.org/about/contact/
Please update all references to our old address in your code so people can continue to contact us (we haven't been at the old address for more than a decade at this point)
Free Software Foundation
I've now deleted all copies of the FSF address from the source files, so this will not be an issue in the future, thanks for reminding me.