Yahoo! Labs is diligently working on enhancing the conventional notion of caching to make it more effective for contextual advertising systems. The team consists of researchers Andrei Broder, Vanja Josifovski, Ravi Kumar, Sandeep Pandey, Sergei Vassilvitskii and summer intern Flavio Chierichetti. In the classical setting, a cache (which refers to a fast but limited amount of memory) is used to sto