Lands Matter decks use permanents and spells that explicitly reward playing, sacrificing, discarding, or otherwise interacting with lands. They overlap heavily with ramp and landfall but encompass far more than simply putting additional lands onto the battlefield.
Titania, Protector of Argoth rewards lands going to your graveyard, while Six can let nonland permanents be retraced by discarding lands. Valakut Exploration converts land entries into temporary card advantage and eventual damage.