Google Now can build up a history of your web searches and then present this to you later as a card. First, though, make sure the option is turned on. So press the Menu button and head to Settings>Accounts & Privacy and from here enable Web History.
Now search for topics of interest; for instance, type in the search bar ‘PS4 vs Xbox One’ or speak ‘OK Google PS4 vs Xbox One’. While this won’t happen instantly, you will find that eventually if you keep searching for content, it will remember this and display a card. If you tap the base of the card, a whole list of topics will appear.