They limited as targetting to 1,000 people because (a) people were using it in very noticeably creepy ways, highlighting thing FB wanted less attention on and (

They limited as targetting to 1,000 people because (a) people were using it in very noticeably creepy ways, highlighting thing FB wanted less attention on and (b) it wasn't making money. Targeting 1 person is not the advertising business. Custom audiences though, is why FB are profitable. The platform before those tools were intriduced (5-8 yes ago) made a lot less.