September is a great time for sports fans. Baseball season is heating up as the regular season begins to wind down, and the playoffs are just around the corner (go Yankees!). If you're a tennis fan, the US Open is underway (will Roger win his 16th Grand Slam?). For golfers, there's the FedEx Cup series. And, oh yes, football season gets underway. There is something for (almost) everyone to watch . . . and talk about.In fact, sports are one of the leading things people talk about. On any given day in America, about 40% of us have at least one conversation about sports, recreation, or hobbies &#8211; that's 120 million people. And it's not just one conversation per day, its closer to three.Which sports, in particular, generate the most word of mouth? It's not even close. Football is far and away the most dominant. Across the course of an entire year &#8211; taking into consideration when the sport is "in season" and when it's not &#8211; 41% of the conversations about sports are about football. Basketball is a distant second, with a 22% "TalkShare&#8482;," followed closely by baseball at 18%. There is then a sharp drop with auto racing at 6%, and tennis rounds out the top five at 5%. Other sports, such as golf and hockey, drop below that with only 3% and 2% share of conversation, respectively.Football is King of Sports ConversationsSource: TalkTrack&#174;, July 2008 &#8211; June 2009All told, we estimate there are 6.6 billion projected annual conversational mentions about football, 3.5 billion about basketball, and 2.8 billion about baseball.The dominance of football is truly impressive once the season begins. As soon as the professional and college football seasons begin in September, conversations about football begin to skyrocket, accounting for almost 60% of all sports conversations in the month of September.At the same time, the share of conversations about baseball plummets &#8211; even though there are still lots of pennant races and the playoffs are yet to come. It could be a time when talk about baseball is still on the ascendancy, but instead we see the relative percentage of sports conversations about baseball drop from its high water mark of about 32% in July, to less than half that amount by the time September rolls around, perhaps as fans begin to conclude their favorite teams won't be in the playoffs.Basketball, meanwhile, sees its peak in March (ah yes, March Madness), when it garners approximately one third of sports of conversations &#8211; a similar level to what baseball achieves in July.Every Day Over 8% of Americans Talk About Football When in Season% of People Talking Daily About Sports, Rolling 4-week AverageFootball is the word of mouth king of sports in large part because it stays part of the national sports conversation throughout the year, even when the sport is out of season. Indeed, its relative share of conversation never drops below 20%. In season it's dominant; out of season, it's still engaging. .So for all you football fans . . . let the games, and the gab, begin.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.Read all Ed&#8217;s MediaBizBloggers commentaries at Ed Keller - MediaBizBloggers.