At last, Google is revealing its split on AdSense: 68% to publishers for content ads, 51% for search ads.
They’re also not revealing splits for YouTube, a program that just started. Note also that big publishers, such as the New York Times Company, have long known — and negotiated — their splits, which also aren’t revealed. A Google spokesman told me last night that these splits hold for classic AdSense pay-per-click ads and also for newer display, CPM ads. They also hold globally.
How do the splits compare? It’s not uncommon for ad networks to take 50% or more. BlogAds, one of the more generous networks, customarily takes 30% on sales it makes and has other models (if sales come through a publisher site, only 14%; they also offer networked sales).