Here are some of the best CPM ad providers for publishers in 2023, based on their CPM rates, ease of use, and payment options:

Adsterra: Adsterra is a popular CPM ad network that offers high CPM rates for publishers. They offer a variety of ad formats, including display, pop-under, and native ads, and have no entry limits, so any website or social media platform can join.

Media.net: Media.net is one of the largest contextual ad networks, with a global presence and premium partnerships. They offer high CPM rates and a variety of ad formats, including display, native, and video ads.

PropellerAds: PropellerAds is a CPM ad network that offers a variety of ad formats, including push notifications, native ads, and interstitial ads. They have a user-friendly interface and offer high CPM rates for publishers.

Google AdSense: Google AdSense is the most widely adopted ad network, serving ads on publisher’s sites to help them with monetization. They offer a variety of ad formats, including display, text, and link ads, and have a user-friendly interface.

Infolinks: Infolinks is a CPM ad network that offers a variety of ad formats, including in-text, in-fold, and in-frame ads. They offer high CPM rates and have a user-friendly interface.

Revcontent: Revcontent is a CPM ad network that offers a variety of ad formats, including native ads, display ads, and video ads. They have a user-friendly interface and offer high CPM rates for publishers.

These are just a few of the many CPM ad providers available for publishers. It’s important to research and compare different providers to find the best fit for your website, blog or social media platform.