@airshipper @frawst Ad tech. Lots of ad tech. It’s not just “hey, Internet Rando, give us some cash and we’ll throw your ad onto the search results somewhere.” That’s chump change they’re not interested in. Instead a lot of it is a huge underlying bidding/auction setup where advertisers constantly bid (often enormous amounts) for favorable placement. https://support.google.com/google-ads/answer/2472742
Last I saw, about 75% of their revenue was ads, with most of the rest Google Cloud services.