Chapter 4 covered stuff such as public domains, copyrights and more. Also, we looked at how we can fetch weather, which is a useful thing since we must know how the day will be before doing something big or just wanting to go outside. We also went over Zillow and realtor to find house for sale and rent. There you are also able to filter your searches which are very useful and less overwhelming for the users to find their dream home. Also, we talked about commerce online and how Facebook did a good job by introducing this feature in their platform which made it easier for us to sell and buy local stuff online.