In the TV show Mad Men, set in an early-1960s ad agency, master copywriter Don Draper says, “Advertising is about one thing: happiness.”

“And you know what happiness is?”

He continues: “Happiness is the smell of a new car… It’s freedom from fear. It’s a billboard on the side of the road that screams with reassurance that whatever you’re doing is okay.”

Maybe that was (somewhat) true 50 years ago, but today’s forward-thinking CEOs, such as Tony Hsieh of the online shoe retailer Zappos, realize that the medium of happiness in business conversations has changed.

It’s become social. And as a result, it’s more real, more valuable and more effective.

An early adopter of Twitter, Hsieh has been a champion of businesses’ adoption of the microblogging site (follow him @Zappos). Smart use of Twitter has not only helped Zappos as a company do things like improve customer service, market itself and promote brand transparency, it’s also made Hsieh “a better and happier person.”

Hsieh will talk about this and more in his new book, Delivering Happiness: A Path to Profits, Passion and Purpose. Check out the video for a preview.

Though there’s obviously a lot more to developing a happiness-based business philosophy than mastering Twitter, Hsieh does give some great guidelines for getting the most out of the platform. For example, he tells Mashable, the tweets he creates fall into one of five categories: Inspire, Connect, Entertain and Educate.

Sure, Don Draper would view someone like Hsieh as soft and squishy.

But how else would you expect a dinosaur to look at a human being?

We took an interest in Amazon’s purchase of Zappos back in July, when the deal was announced as a possibility. After all, fly kicks and sophisticated reading material are the two things one must have in place before posting up at the local coffee shop.

In all seriousness, though, $900 million — the pricetag three months ago — was mindblowing. But when Amazon announced yesterday that the retail giant would buy the shoe/clothing giant for a wh-wh-whopping $1.2 billion, we about jumped out of our Chucks.

But when you look at what Zappos offers in terms of superior customer service and innovative use of social media, you get the picture of one smart — and lucrative — company.

Customer Service: Zappos’ free shipping and free, 365-day return policy are already well known, not to mention all the other little things Zappo’s does to give its customers all the satisfaction of being in a really, really good shoe store without leaving home.

Social Media: As an extension of its service-oriented (versus price-oriented) approach to sales, Zappos has embraced social media. CEO Tony Hsieh is a savvy Twitterer, promoting company community-building with its customer base. His tweet sharing the memo that went to his employees about the Amazon deal is a perfect demonstration of transparency’s value to ongoing brand development.

Zappos also interacts with customers through its blog, providing content that’s fun to keep up with even outside of the activity of shopping for shoes, such as this completely random Lady Gaga “interview.”

On the more high-tech end of things, have you checked out Mappos? Now this really is amazing. It’s essentially a map of the US that, once you bring up the page, shows instantaneously what people across the country are ordering, and where. It’s hypnotic, watching people shop online in real time: “Oh, someone in Evansville, IN, just bought a pair of Addidas Sambas”…”Oh, someone in southeastern Washington just bought Beatle boots”… and so forth. It’s great if you’re looking for fashion ideas; click on a shoe that pops up, and it takes you straight to where you can buy a pair for yourself. And the interactive rating system absolutely rakes in up-to-the-minute customer feedback.

Zappos, darn it, you earned that $1.2 billion payday. That’s what we call walkin’ hard.