Game publishers have been inserting advertisements into video games almost since games were first developed. But what began as static in-game product placements such as billboards advertising a publisher’s upcoming title in the 1970s has become a much more sophisticated marketing tactic — and a potentially lucrative revenue stream. “The medium’s been growing for about six years now, and both Microsoft and Google have bought companies in this space — Massive and Adscape, respectively,” Andrew Frank, a Gartner Research analyst, told the E-Commerce Times.