Since most services are not widely marketed online, the BPP has to use proxy measures: it calculates health-care costs by weighting changes in the price of wages, energy and drugs.

Plausible upgrades could take the form of greater online gaming features, including the ability to handle microtransactions and, by proxy, social games and free massively multiplayer online games.

A user can have a static Web page online several ways: from using the browser cache, to having a local caching proxy, to just downloading the Web content to disk.