There’s been quite an uproar about Twitter acquiring and developing in-house some functions once created by third-party app developers. While the microblogging service may be closing some doors for entrepreneurs in the online world, Twitter’s bad buzz means we risk missing untapped opportunities it offers to real-world businesses. If companies can tap into that potential, then all the hubbub over Twitter’s “hole-filling” becomes mere noise.

Think of eBay, which grew into a vast marketplace by enlisting basement bargain hawkers. Or Google, which opened up advertising to mom-and-pop shops. Twitter could play a similar role by changing how businesses find customers.

Take, for example, mobile food trucks such as the Kogi Korean BBQ truck in Los Angeles, or a host of similar ones in San Francisco. Unlike traditional food carts or lunch trucks, this new generation of mobile eateries has embraced Twitter to communicate truck locations and daily specials to tens of thousands of followers.

That’s because Twitter is a selective broadcasting tool, unlike the communications media it’s supplanting. Direct mail is far too slow. Email is too noisy. Text messages are too expensive and annoying. And instant messaging is took desktop-bound and unwieldy. Businesses which understand those distinct characteristics can take advantage.

By cleverly turning its Twitter followers into actual followers who chase down treat-toting trucks, Kogi Korean BBQ has scored a lot of press and some hard cash. Its Twitter feed has 61,000 followers tracking four trucks. Best of all, they’re not worrying about the value they’re adding to Twitter or if Twitter will pounce on their creation for their own gain. They’ve come up with a model that builds on top of Twitter, rather than filling in holes that Twitter missed. And that’s just one small business in Los Angeles. There are far bigger examples of companies using Twitter for real-world advantage.

One could argue that Zappos, the online shoe retailer, beat Amazon.com at the e-commerce game by using Twitter to bolster customer loyalty. Zappos CEO Tony Hsieh tweeted himself on the company account, personally answering customer queries. It was a huge gesture to Zappos shoppers that didn’t tie up too much of Hsieh’s time. Amazon.com CEO Jeff Bezos could never match that kind of hands-on touch using Amazon’s old-fashioned Web and email customer support — and Amazon.com eventually bought Zappos late last year for $1.2 billion.

The interests of these businesses are far different from Twitter developers’ concerns. Tony Hsieh doesn’t need to worry how Zappos customers get his words, since Twitter subscribers can choose to receive messages on the Web, by SMS, or on a mobile app. Kogi’s chefs don’t need to learn how to code an API. They can just post their messages. And watch their businesses develop. That’s the real Twitter opportunity.