Uh, they literally paid MILLIONS for the antispam company POSTINI and thats what the original anti-spam features for GMAIL are based on... in the last 18 months or something, google apparently deleted that tech from their stack, I posted about this when I first started having so much spam inbox my gmail....
So yeah - THEY _supported_ the product by paying millions for it...
And now in 2022 any gmailinbox is fn full of spam...