Funny you should mention vouchers - it reminded me of the article discussed here[1], which likened advertising with Google to handing out coupons to people who

Funny you should mention vouchers - it reminded me of the article discussed here[1], which likened advertising with Google to handing out coupons to people who are already in your store [1]https://news.ycombinator.com/item?id=21465873 https://news.ycombinator.com/item?id=21465873