American Idol was again the most watched show on television this year, according to the Nielsen ratings for the 2008-2009 season. But the Fox Broadcasting juggernaut was not the king of "buzz" on TV for the season. That honor goes to CSI on CBS, TV's word of mouth winner for the second year in a row, according to my firm's latest word of mouth tracking research.To be sure, American Idol enjoys remarkable success as a word of mouth brand, taking a strong second place behind CSI with a big rebound over its more lackluster results of a year ago. Still, many may find it surprising that the CSI franchise generates even more conversation than American Idol.Overall, it was a strong year for TV when it comes to word of mouth. For the season as a whole, WOM levels were up more than 8% versus the previous season. And for the second half of the season, they were up a very impressive 15%. Perhaps during these difficult economic times, television not only provides a much needed diversion, but also gives people something to talk about other than grim economic news. Top 10 Programs in Terms of Ratings &amp; WOM for 2008-2009 Nielsen Ratings Word of Mouth Ranking* 1. American Idol (Weds) 1. CSI 2. American Idol (Tues) 2. American Idol 3. Dancing with the Stars 3. House 4. CSI 4. Lost 5. NCIS 5. Family Guy 6. The Mentalist 6. Dancing with the Stars 7.&#160; Dancing with the Stars (Results) 7. Heroes 8.&#160; Sunday&#160; Night Football 8. NCIS 9.&#160;&#160; Desperate Housewives 9. 24 10.&#160; Two and a Half Men 10. Grey&#8217;s Anatomy *Source:&#160; Keller Fay Group&#8217;s TalkTrack&#174; &#160; &#160;Rounding out the word of mouth top 5 are three shows that do not appear in the Nielsen ratings top 10: House, Lost, and Family Guy. (House and Family Guy have particularly strong word of mouth among teens. So does Gossip Girl, by the way: it is the WOM leader among teen girls.)Other WOM leaders among TV shows: Dancing with the Stars, Heroes, NCIS, 24, and Grey's Anatomy. Dancing and NCIS are both top 10 shows according to the Nielsen ratings, while Heroes, 24, and Grey's Anatomy break into the WOM top 10 despite ratings that are not quite as high.Which of these top 10 shows have the greatest word of mouth momentum on their side; in other words, who showed the most improvement from last season? The three biggest gainers were House, 24 (which was off the air last season, but still managed to generate reasonable word of mouth, based no doubt on sales of DVDs and video downloads), and NCIS. Each of these shows saw an impressive increase of approximately 6 million conversations per week this season compared to last.Another way to measure word of mouth power &#8211; beyond sheer numbers of conversations, or growth in the amount of weekly conversation &#8211; is to look at the quality of the word of mouth. If we look at shows that generate a substantial percentage of positive word of mouth, and subtract conversations that are either negative or mixed, we get a score that we call the net advocacy score. Shows with the highest net advocacy levels are NCIS (with a staggeringly strong net advocacy score of 92), followed by Two and a Half Men, 24, CSI, and Family Guy. House also does well on this metric. American Idol, in contrast, is far more polarizing in its word of mouth with a net advocacy score of only 40. Either you love Idol or you hate it, but perhaps from the producers' perspective they happily subscribe to the rule that it doesn't matter what you say about me, as long as you spell my name right.So what do we conclude from all this? Traditionally, advertisers have been focused primarily on audience size, but in this environment more and more of them are looking for "intangibles" such as audience engagement, as an engaged viewer is apt to be talking about what he or she is watching on television.In many respects, American Idol is built for engagement, with direct audience participation in the outcome, as well as lots of online and watercooler chatter about its contestants. But more traditional formats like CSI, House, Lost, and Heroes are also generating lots of buzz, which is an important lesson for marketers and television executives alike.Perhaps the most important story, however, is the fact that in these challenging economic times, television is capturing a bigger share of the national conversation. It's another reason, perhaps, for the broadcast industry to remind the marketplace, in the words of Mark Twain, "The rumors of my death have been greatly exaggerated."Ed Keller, CEO of the Keller Fay Group, has been called "one of the most recognized names in word of mouth." The publication of Keller's book, The Influentials, has been called the "seminal moment in the development of word of mouth." Ed can be contacted at email@example.com.