Google is currently in the process of adding a new feature to its eponymous app for Android. Simply put, it's a new widget that shows up under the big white persistent search bar in your launcher. The widget is transparent and can show you small tidbits of information, such as the weather at your location, commute time, or local information.
Above is the way it looks. The screenshots below will help guide you in order to enable it. Go to the Google app's settings and then choose Widget, and turn it on. Note that as with all things Google-related, this one's part of a staged rollout too, so you may not even see the Widget option yet.
Oh, and even if you do, and you enable it, the widget itself might now show up immediately - or at all. The functionality probably requires a server-side switch too, and Google seems to be taking its time in doing that for all users. One thing to note is that you are apparently required to have the Google app version 18.104.22.168 or later in order for this to work - and to get that you may have to register as a beta tester for the app (you can do that from its Play Store listing, but the usual warnings about running beta software on your daily driver apply).
One final note: the new widget might not be shown at all times, even after everything is enabled for you (including that server-side switch). Hopefully this will change in the future, and it will gain support for more Google Now cards.
Hate it. The Now search bar now obscures an important part of my live wallpaper.
Yes!! I got my new transparent notification on the launcher. Kudos Google.
Unfortunately, it is already on and preloaded on every Nexus devices and there is no option to remove it anymore, the only way to remove it is to buy and install 3rd party launches and trust them with permissions on critical security matters and live...