In Google’s ideal world, a mobile app is not a closed space but an open one — a layer for services that can easily connect with one another, like the Web. Ergo, the introduction last month of a method for streaming apps directly inside Google search, sans download.

It was a very limited rollout, but an important one in Google’s move to create a world in which it retains its position as portal to the consumer Internet.

Now Google is expanding that streaming capability to ads. Its mobile ad unit is adding two new formats for developers to promote their apps inside of other apps. The first, called Trial Run Ads, lets smartphone users test out an app — in all likelihood, a game — for a minute without downloading it. It will work for anyone running ads on AdMob, Google’s mobile network, which serves around 650,000 apps. Developers only pay if the user clicks to install; and, theoretically, they will get more eager downloaders, solving the nagging issue of neglect for apps.

The second deals with more lively formats for full-screen, or interstitial, ads. Google may take some heat for this, as it recently moved to de-rank full-screen mobile ads in its search results, infuriating many. That was only about keeping search undiluted and not meant to impact the vast (and remunerative) world of ads within apps, according to people familiar with the matter.

The two new formats come from Sissie Hsiao, who was promoted to lead Google’s critical mobile ad division in June.