Yahoo announced the acquisition of RightMedia — it had already been a “strategic 20 percent investment” — a wise, counterplay to Google’s recent $3.1B acquisition of DoubleClick. Doesn’t seem to be a hasty reactionary move as Right Media’s Exchange system could be a boon to Yahoo’s publisher network and it’s new Adwords-like search advertising platform code-named Panama. Yahoo CEO Terry Semel’s optimistic blog post is here. New York Times gets a jump on the story here. A conference call will take place Monday morning and surely the industry-watchers will have more deets and analysis.