One of the projects i've daydreamed about is an app where you sign up for issues that you care about like water privitization or palm oil etc, and then you scan a barcode and get a report of whether the product is connected to any of those problems. You will then (hopefully) not buy the product and maybe hit a button in the app saying that you chose not to buy it.

Every month, the app collects the data from its users and produces a report: "Dear Nestle, this month you lost $X of revenue on account of people boycotting you because of this or that."

I think it's important to send some kind of negative feedback to companies.