They absolutely do. Every sponsorship you see on a podcast or a youtube video or a streamer is a contextual ad. Many open source sponsorships are actually a form of marketing. You could argue that search ads are pretty contextual although there's more at work there. Every ad in a physical magazine is a contextual ad. Physical billboards take into account a lot of geographical context: the ads you see driving in LA are very different than the ones you see in the Bay Area. Ads on platforms like Amazon, HomeDepot, etc. are highly contextual and based on search terms.