FAQ: Sessions For A Particular Search Engine
How can I see only the visitors that came from a particular search engine?
Direct that search engine to a particular entry page, and then use global filters to show only sessions for that page.
Some information of this type is available in the "Search engines" view -- you can zoom in on a particular search engine by clicking its name there, and then switch to the top visitor hostnames view to see which hosts came from that search engine, and other information about the traffic from that search engine. But that only works for the first click, because after that, the log data no longer lists the originating search engine (the referrers are internal from that point on). So you can see how much traffic search engines brought, but what if you want to see what the visitors from a particular search engine did after they came to the site?
You can do that by using custom entrance pages and Global Filters. Start by pointing each search engine to its own URL, where possible. For instance, instead of pointing Overture to http://www.mysite.com/index.html, you can point it to http://www.mysite.com/index.html?source=overture Once you've done that, then all traffic from Overture will initially arrive at the /index.html?source=overture page. By showing only sessions containing that page (see Sessions For A Particular Page), you can show the session activity of Overture visitors, including what paths they took, how long they stayed, and more.
You can do the same thing for any search engine, advertising campaign, or link exchange that allows you to choose your URL. It won't work quite as easily for broad search engines like Google, which let people enter your site at any point, but it's still possible to "tag" the URL similarly using a log filter -- see Tracking Conversions.