Last year, Google launched Ad Planner as a way to help media buyers plan their advertising campaigns. Now, they've updated their traffic models to improve planning.

Here are the updates:

• Added Unique Visitors (cookies), a new cookie-based metric, to help you cross-check and compare metrics, similar to Google Analytics unique visitor metrics.
• Changed Unique Visitors to Unique Visitors (users) so it's clearer that you're reviewing estimated numbers of real world visitors.
• Placed the Unique Visitors (cookies) and Unique Visitors (users) metrics on a site's profile page so users will have a more comprehensive view of how a specific site can support their media planning.
• Added country demographics for Australia, Brazil, Japan, and Switzerland, which brings the demographics total to ten countries
• Created Pre-defined Audiences that represent commonly used audiences. Uers can experiment with various criteria without having to manually select them.