Content Targeting
Content Targeting - Advantage: Google
You could write a book about how content targeting has developed at these two companies. Google's reach is wider and it has developed a bit of an odd way of improving advertiser ROI: they discount the amount paid out to publishers based on a predictive formula that may give advertisers bargains on clicks predicted to be of low economic value (they call this "Smart Pricing"). Google now offers a second flavor of content called Site Targeting. With the recent DoubleClick acquisition, it looks like the company shoring up some shortcomings toward becoming the gorilla in the space.
Ad Formats -- Headstart: Google. Big Plans: Yahoo
Google is farther along in allowing display ads and video ads to be part of the advertiser's mix. Yahoo has just launched mobile advertising and its plan is to include TV in the distribution mix in the future. Yahoo also plans to support all kinds of ad formats, from graphical ads to rich media.
Editorial Review Process - Even Score, But Yahoo is Playing Catch Up
On both engines, ads are mostly manually reviewed. The manual review process is basically invisible to the advertiser, and many ads go up quite quickly. Once a major point of departure, both organizations now use automation to speed the editorial process. For example, a low impact term like "snow gloves" is usually automatically reviewed. Sensitive terms like trademarked terms, pharmaceuticals, adult content, et cetera, are flagged and pushed directly through to manual review.
One apparent difference is that on Google, ads go up on Google.com until they're manually reviewed, and then they're placed on the entire Google network. On Yahoo, ads go up on the entire network and then are manually reviewed.
Agency Master Accounts - Advantage: Google
Google had some hiccups when it built out the My Client Center functionality, but today it works quite well. Yahoo currently has no agency console to speak of, but it's on their to-do list.
Next: Matching Options