I'm sure much of this information is public on their profiles to begin with; with a simple web scraper, you can acquire information about millions of fb account

I'm sure much of this information is public on their profiles to begin with; with a simple web scraper, you can acquire information about millions of fb accounts and their respective email addresses. OFC there's an oversupply since they can give out an unlimited amount of copies of this same million FB entries. Big Data is great because it's super re-usable and can be purposed for anyone's specific need.