During her keynote at SES San Jose, Marissa Mayer, Google's vice president of search product and user experience, deemed cost per action (or CPA) "the Holy Grail." She said Google is making moves toward CPA as a more ideal auction-based pricing model, but that's still a long way away. CPA means that someone pays when a user completes a more involved transaction. So in the case of an airline, the company pays every time a user clicks on its ad and purchases a plane ticket. Only when both deeds are done does the airline pay, but it will most …

Martin Veitch takes a look at Microsoft's experimental Tafiti search engine, which requires the company's Silverlight cross-platform, a cross-brower plug-in intended for rich media applications. He finds the interface interesting with its virtual index card, carousel for search types, and ability to store results. But Veitch's basic assessment, after speaking with other experts, is that the engine serves primarily as "eye candy" and a showcase for the Silverlight technology. Its biggest drawback is a reliance on Microsoft's Live Search, which he said yields largely relevant results, but not as good as those found elsewhere.

Google's official blog announces that its change in formula is now live -- the one that considers an ad's maximum CPC rather than its actual CPC when determining ranking. "Since announcing this improvement to the top ad placement formula, we've received lots of questions from advertisers who are curious about how their accounts may be affected. Advertisers with ads in or near a top spot may begin to see a change in the average number of clicks these ads receive, and also in their CPCs," the blog reads. "The degree to which your clicks and CPCs may be impacted will …

Here's coverage of a paid links panel entitled "Are Paid Links Evil?" from SES San Jose that included OMMA magazine columnist Todd Friesen of Range Online Media. During the panel, Google's Search Quality Engineer Matt Cutts noted that in the offline world, the FCC demands disclosure of all paid marketing activities. In his opinion, when that carries over to the Web, it must include disclosure for both humans and machines -- and he explained just how he thinks this should be done.

Netconcepts' Stephan Spencer lays out in detail the 12 common mistakes that even the top SEOs make in terms of their blog optimization. Then he explains how to alleviate them. The list starts with allowing tags to be auto-generated and ends with using suboptimal anchor text when linking internally.

Henry Blodget offers a detailed analysis of the revenue contribution from the video ads on YouTube that Google announced on Tuesday. His most aggressive forecasts range from a $450 million contribution to $13 billion. (Read the blog for all the variables put against these numbers.) YouTube's revenue won't likely be material to Google for at least a year or two and possibly more, Blodget says. What's more, the impact on the bottom line will probably be even less pronounced, he says, because serving a video ad, even for Google, is far more expensive than serving a text link. At a …

During his keynote Q&A at SES: San Jose, Ask.com CEO Jim Lanzone said Ask3D is just the first of a series of changes planned for the next 12 months. On the list is a project designed to make data fresher and better, getting it up to the levels that will give searchers much better results.

Blogger Rich Skrenta offers an analysis of Jason Calcanis' human-powered search engine. If Mahalo doesn't get SEO traffic from Google searchers, he says, it will have to morph into something else. In the past a site like Looksmart that had lots of editorial-generated directory content could sell that to other portals. But content is now commoditized, so Skrenta doubts there is big licensing revenue in Mahalo's future. Skrenta then gives a detailed list of recommended modifications, of value to anyone in the space. Lots of good give-and-take at the end of this one, including some back-and-forth with Calcanis.

While the ideal for in-house search marketing is to perform all tasks related to search marketing internally, sometimes it's necessary to get help from the outside, says Simon Heseltine. Heseltine outlines just when it makes sense to go outside, and offers guidelines for making the relationship work. Paramount is an honest discussion of expectations to establish the right level of trust.

Hallie Janssen covers a session from SES: San Jose detailing how to establish benchmarks for your site. She lays out step-by-step the ways to determine how visible the site is, how effectively it's reaching the target audience, and the ROI delivered. Learn how to figure out your competitors' keyword bid strategy, and more. It's all in here.