I'd never heard of searchmash, so I tried the 3 yo link to searchmash.com. It still works.
Today it reads ... "searchmash has gone the way of the dinosaur".
Techcrunch as a Nov 2008 article on the demise of searchmash. Looks like Google used it as an unbranded lab for a while, before they transitioned to their current "lab" strategy.
Now you know.