If Facebook bought Twitter, sports fans would rejoice.

Through such a fantasy merger, there’d be only one “identification service” to worry about when you wanted to broadcast your sports opinions to the world. That would be a welcome relief from the two-headed monster that now rules the kingdom of sports smack, the beast with tweets on one side and Facebook posts on the other. The big question is whether sports fans will continue to feed both monsters, or whether one will prevail, like Highlander, to rule them all.

Winning the ID Game

Before we get too deep into bad movie cliches, it’s worthwhile to take a small step back and wonder at how quickly Facebook and Twitter have basically won the battle for user identification, or authentication. In the days of Grampa Internet, individual sites would try to get readers to “log in” or “register” with unique passwords and IDs. That led to a frustrating era, just now ending, of having to remember multiple screen names, logins and places to track conversations.

Then came Facebook and Twitter, who after a short while made the smart move of making users’ identifying features portable — meaning you could use your Facebook or Twitter screen persona to log in to web sites and blogs, instead of having to remember each site’s unique ID. Boom, game over. If you are an active sports commenter, you are probably already on Facebook and Twitter and spend little time anywhere else.

Though ESPN still requires you to have a site-specific login to comment on their story “conversation” sites, it’s easy to see where the worldwide leader is going, with constant beckonings to “tweet us your questions” to be answered on talk shows, and with an unending parade of Facebook polls and comment come-ons. It’s pretty amazing that two startups like Facebook and Twitter could completely trash the user-ID-accumulation schemes cooked up by major media properties since the web began. What might be more compelling is the coming clash between the two new titans, who each have attributes that make them more compelling to sports opinionators, depending upon the situation.

Twitter: Fast, fun and the athlete’s domain

Though by far the smaller of the two services, Twitter is the new darling of the sports world, in no small part because it has become the favorite platform for pro athletes. Unlike a website, a blog or even a Facebook page, a Twitter account needs only some short thoughts and a smartphone — two things that are front and center in the pro athlete’s world of 2011.

In its short life Twitter has changed the face of many facets of media production, including coverage of wars and revolutions. In the less-meaningful but not less-followed world of sports, Twitter has become the de facto news wire of the sporting world, with teams, athletes, fans and followers all adding to and taking away from the information stream.

For the average fan, Twitter is like a fire hose of comments and information that never slows down, and is as wide and diverse as who you choose to follow. From a commenter standpoint there is the problem of having to make your voice heard in the crowd, but by just signing up and tweeting you still have a chance to see your name or fan-tastic psuedonym flashed on the ESPN screen. The low barrier to entry and instant gratification make Twitter the first choice for a lot of new Internet sports enthusiasts.

Facebook: Best for long opinions, monetization

In terms of really building an online social presence, however, nothing beats Facebook, especially when it comes to easily finding a home for photos, videos, long opinions and opportunities to build a business. For teams, athletes, vendors and sponsors in the field, a Facebook page is a no-brainer as it gives easy access to the hundreds of millions of folks who already have a Facebook ID.

For the average sports fan Facebook is probably a lot easier to understand than Twitter, and the post/comments structure lends itself to longer “conversations” on a single topic or event. The recent integration of Facebook comments under blog posts is a step toward Facebook’s plan of social-activity domination: Simply put, the service wants to make it easy for you to record your every thought, “Like” and observation in some form that can be embedded inside a Facebook wrapper.

And by allowing integration of applications and even stores on Facebook pages, the service is equally attractive to teams, vendors and sponsors who want to extract dollars from the multitudes of fans. The commerce-friendly platform is what gives Facebook the sporting edge right now, but Twitter is gaining ground quickly, thanks to its Google-like ease of use.

Who Wins? Or do they both survive?

Right now, connected sports fans as well as athletes, teams, schools, advertisers and vendors in the sports-fan space all are most likely active on both services, depending on the time of day or situation. While much of the live commenting action has moved to Twitter thanks to its instant-publishing stream of thought, the more leisurely searches for information and interaction still take place on websites, blogs or Facebook pages, meaning that you can’t live on simply one or the other right now.

While that means there is still the headache of “do I post to Twitter or Facebook,” there remains the possibility of some future integration, perhaps by a business arrangement once both firms go public as is widely expected. Though there do exist services and techno-solutions that will replicate your Facebook posts onto Twitter and vice versa, the different styles of communication on either platform make such services an inelegant compromise at best. Will those differing styles keep the beast’s two heads alive indefinitely, or will one succeed in chewing through the other’s throat? Whichever way it goes, it will be a fun movie to watch play out over the near term future.