The Lovemeter is a page which shows us and keeps track of total interactions made on the game. The goal is to fill the bar up and reach a set amount of interactions.
Once the bar is filled, all interactions on the next day will count twice.
You can help filling it by interacting with Pokemon. Each Pokemon you interact with counts as 1 interaction Point.
On the right, you will see a bar. It will need to be filled to the top. In the center of the page, there will be a green box. On the left, it will show the total interaction made. On the right, it will show us the goal we need to reach.
Once the goal has been reached, all interactions on the next day will count twice, and the bar will reset back to 0/20,000,000.
On 06/Oct/2017, the Lovemeter goal has been reduced to 15,000,000 interactions.