Ah, the power of youth. It’s intoxicating, alluring, dynamic, vibrant, and a bit pushy. Maybe not so coincidentally, these are all similar attributes associated with entrepreneurs.

Anecdotally, evidence is everywhere of a surge in entrepreneurship and business ownership among young adults. At recent events—TechCrunch Disrupt or demo days at TechStars and Y-Combinator—startup founders have a decidedly youthful appearance. Organizations like the Young Entrepreneur Council or Under30CEO are growing and capturing increased media awareness.

But who are these new masters of the universe? How do they differ from the old guard, those baby boomers and early members of Generation X who still comprise a sizeable majority of business owners?

In a new study by The Business Journals, which, like Portfolio.com, is owned by American City Business Journals, a distinct picture emerges. Each year, The Business Journals survey approximately 2,200 owners and top executives of small- and midsize companies to explore their attitudes about the economy and their own businesses. This year, the researchers dove deep into the numbers to see just how much of the survey sample fell into a younger demographic (here, categorized as under 40) and how their views compared with older business owners.

Here’s some of what the survey found. For more results, click here to explore an interactive detailing the comparison of those business owners 39 and under with those 40 and over:

• Despite the allure of youth, the vast majority of surveyed business owners were in the above-40 camp. Only 15 percent were 39 or younger, with the average age of this subset being 34.
• The average household income of the under-40 set is $133,500, about 15 percent less than older business owners. Other differences: The younger group is better educated, has a stronger presence in the South and West, and includes more Democrats and Independents.
• Younger business owners are more concerned about having enough time to spend with their families, dealing with stress, and finding a trusted business adviser. Conversely, older business owners worry more about national issues: the state of the economy, the rising cost of doing business, and the impact of health reform.
• The younger business crowd sees technology as being a vital component to doing business effectively, views wireless as being critical to their operations, is connected more hours a day to computers and mobile devices, and see the Internet as a vital tool.
• Younger owners engage in more physical activities like going to the gym, doing yoga, jogging, or engaging in martial arts than those over 40. On the flip side, older business owners do more fine dining, and they support the arts and golf more than their younger brethren.
• The younger set has a greater percentage of minority-owned companies; 19 percent, compared with the 9 percent of businesses owned by those older than 40.

Godfrey Phillips, vice president for research for The Business Journals, said that despite the difference in raw numbers between younger and older business owners, the power of the younger set can’t be ignored. “If you don’t listen to them, you do so at your own peril,” Phillips said, adding that it’s this audience that should be the litmus test when selling B2B brands.

Among favored brands, for example, younger business owners like Virgin America, while older owners prefer other carriers. In computers, younger owners like Apple, while older ones like HP and Toshiba. And with financial services, younger owners like E*Trade, while older ones like Fidelity and the Vanguard Group.

“With [the under 40], it’s what the future looks like,” Phillips said. “If you’re not one of the preferred brands, I would take a look at your strategy.”

If actual sales growth and the vision of future sales growth are used as criteria, the under-40 set appears to have a far greater entrepreneurial bent than their older counterparts. In both of these areas, younger owners far surpass the 40-and-older group:

• Nearly a third of those surveyed reported leading fast-growing companies, those defined as having 11 percent or greater sales growth in 2010. Among business owners 40 or older, only 16 percent reported that kind of sales growth.
• More than three quarters of those under 40 said they wanted to “get to the very top of [their] field/profession.” That compares with 59 percent of older business people who said the same thing.
• Just about as many younger business owners, 72 percent, said they expect their companies to grow significantly over the next few years. Among those 40 and over, that optimistic attitude is shared by 55 percent.

Finally, younger business owners are far more social than their older peers. Eighty-eight percent use a social network, while 70 percent say they incorporate such networks into their marketing plans. For those 40 and older, the numbers are 68 percent and 47 percent, respectively. Of the networks, Facebook is far and away the most popular, with 83 percent of those under 40 saying they’re on it. In a distant second spot is LinkedIn, with 35 percent.

“What’s interesting here is that younger business owners and entrepreneurs are already fully into social networks. They’ve been using them for eight to 10 years. So now we have to ask: What’s next for this pivotal group?” said Jessie Shaw, The Business Journals lead strategist who wrote the report.