The timing of the notification is worth noticing. The notifications shows up as the user is launching the browser of any competitor to Safari. Clicking the Later button in the notification or just ignoring it will delay the notification for three days. The notification will then show up again and again until the user eventually agrees to click Try Now or learns to live with the notification.
Trying out Safari will not immediately change the default browser on the system. The user will, however, be asked upon quitting Safari to change their default to Safari. More on this later.Daniel Aleksandersen
Hmm, could this be the first step to Apple making Safari the only browser allowed on OS X (just like it is on iOS since day one)?