Because the paying users subsidize the free product, they pay the free lunch. Meanwhile google, like most big platforms, is (almost, see comment) entirely without payment, instead subsidized by ads (and of course the sold data); with gmail you’re not paying with money, but with your attention (and your data).
Because the paying users subsidize the free product, they pay the free lunch. Meanwhile google, like most big platforms, is (almost, see comment) entirely without payment, instead subsidized by ads (and of course the sold data); with gmail you’re not paying with money, but with your attention (and your data).