Ever since Google Now was introduced on Android 4.1 Jellybean it became of the most unique features of Android. But then Google brought it over to iOS, unfortunately it's not as integrated though. It provides users with a personal assistant in a way, learning the user's behaviour, preferences and more. It can even tell when you go to work and how long it'll take to get there, taking into account traffic.
To expand the Google Now experience, Google is now bringing it to Chrome. Google is rolling out the feature across Chrome users over the next few weeks.
To get it working you just need to be signed in with the same Google account used on your Android or iOS device.
However if you want to force it to start working right away, you can put chrome://flags into your browser and search for Google Now, then enable the notifications.