The spam filter is a product. And if it doesn't work, like legitimate mail getting marked as spam, they will lose business. Just look at Yahoo where it's curren

The spam filter is a product. And if it doesn't work, like legitimate mail getting marked as spam, they will lose business. Just look at Yahoo where it's currently impossible to get white-listed, who are losing business because of this. (Yahoo mail was as big as Gmail is now about 15 or so years ago)