This app started out as a way to view Google News on the author's phone but now encompasses Google+, Google Maps etc. The idea is to be able to access the Google web apps without having to log into Google on your browser, so that you can browse privately. It is a good way to access the Google webapps if you have an AOSP-based ROM and reject the proprietary GApps. Also the webapps are less bandwidth and battery-hungry than their native counterparts.
Links to external sites (such as news articles, etc.) will be opened in a regular browser, thus keeping the Google authentication sandboxed in the app.
Although APK downloads are available below to give you the choice, you should be aware that by installing that way you will not receive update notifications and it's a less secure way to download. We recommend that you install the F-Droid client and use that.Download F-Droid