Very soon it will be even quicker and easier to install an app on your Android device. Google plans to roll out an update which lets users install apps directly from search results. This basically lets you bypass having to go directly to the Play Store entirely if you are confident you just want to install the app.
The folks over at Android Police were the first ones to report it. Here's a quote from their article with a few more details,
It appears that the feature is still in the early stages of a wide rollout. Perhaps they are still doing some testing, or perhaps it is just taking a while to filter out to everyone. Either way, keep an eye out for the ability to use the feature.You can test this yourself by opening the Google app and searching for the name of an app. It will appear at the top of the results with an install button—this part is true for everyone. However, most people are booted into the Play Store when they tap it. Those with the new feature will see a permission popup just like they would in the Play Store, then a miniature Play Store frame appears so it can be installed. It's really neat.
This might only work from the Google app, not Chrome (that's common with similar features). Some users report that this started happening a month ago or more, but only recently has it started appearing widely enough that we got tipped about it. Take a look at your search results and you might find it's already live for you.