The site has already disappeared.
According to Massie Ritsch, the department had no money for Doing What Works. He said in an e-mail:
The ED office managing Doing What Works did not have sufficient funding to continue operating the website and producing new material, but we are working to place the archive of resources on another site for educators to use.
I won’t mention the irony in the fact that department spends millions on school reform that has no proven record of success but ran out of cash for its Doing What Works website.