Facebook users spend upwards of 12.7 percent of their time on the site, according to a comScore study. Of course, wherever consumers live, businesses are sure to go. But to what end?

Chief marketing officers surveyed by BazaarVoice and the CMO Club were likely to say their business engaged in at least three forms of social media. But nearly 35 percent of all CMOs didn’t know if their Facebook presence yielded any return on investment.

“If you’re a company who’s spending employee dollars, spending employee time, paying agencies, if you’re actively engaged online and it’s costing your business money, it’s irresponsible not to measure some aspect of that time spent and of that money spent,” says Eric Peterson, founder of Twitalyzer, a Twitter analytics start-up based in Portland.

Quantitatively measuring a brand’s online influence is a relatively new idea, but it may be one of the most important developments in online marketing since Google AdWords. Understanding how your company interacts with its online community, and knowing which tools are effective in the ultra-specific world of the Internet, is crucial for driving your brand’s overall success.

Several young and creative companies have stepped up to the plate with unique ideas for various influence metrics. Many of them function similarly, at least at first: After plugging in your Twitter, Facebook, and LinkedIn profiles, sophisticated algorithms compute your company’s data and visualize the results in pie graphs, scatter plots, flow charts, or even a simple two- or three-digit number. Some sites even offer specific recommendations on optimal hours to engage your clientele. You’d be surprised at how many ways your data can be interpreted.

We spoke with founders of four of the top companies that measure online influence—Klout, PeerIndex, Twitalyzer, and Crowdbooster—about precisely how their services measure online influence, and how you can best employ them.

“Going back historically, every broadcast medium has been measured,” notes Joe Fernandez, founder and CEO of Klout, a social-media analytics start-up based in San Francisco. “Television is measured, radio is measured, newspaper is measured… People are now broadcasters. We all have the ability to have an impact on our network, so our ability and our desire to understand that, and the need and the market for that, is why Klout exists.”

Today, millions and millions of individuals and companies link Klout into their Facebook, Twitter, and LinkedIn accounts to measure social influence.

Klout measures more than 35 different variables grouped into three basic areas: True Reach, the size of the engaged audience; Amplification, the likelihood content will be acted upon by others; and Network, the influence level of the engaged audience. Your company’s True Reach, Amplication, and Network combine to create the overall Klout score, which is a number 1 to 100.

“[Klout] is far from perfect,” admits Fernandez. “What we’re doing is infinitely complex. Every day, our score gets better, the quality of our analytics we’re doing gets more accurate… You never hit an endpoint here. It’s always a living, breathing system.”

OK, so you have a score. What does it mean? If your online presence achieves a score above a certain threshold, you are deemed “influential,” and basically eligible to enjoy the fruits of being an influential person. Klout connects influential members and brands together, so those with high Klout scores may receive a slew of luxurious benefits.

According to an article in the Wall Street Journal, after tweeting about a trip to Las Vegas, 25-year-old PR account executive Katie Miller was invited to a lavish party for influential individuals in the Upper West Side in Manhattan. She was singled out by the party’s sponsors—the Venetian and Palazzo hotels in Las Vegas—due to her high Klout score.

“We have people who are getting jobs because of their Klout score,” says Fernandez. “We have hotels in Vegas that use the Klout score to upgrade rooms, so there’s real value. Klout does actually have real impact on people’s lives.”

“When I was working for a blogging platform in Europe, we started to investigate this idea that bloggers were quite authoritative voices on certain things,” says Azeem Azhar, founder of PeerIndex, a social capital analytics start-up based in the United Kingdom. “Ideas brewed for a while and I was constantly interested in this notion that authority was moving away from institutions granting authority to people. We had to build some technology to find out who actually had some social capital on [any given] subject.”

PeerIndex, launched by Azhar in 2009, draws many similarities to Klout. In addition to linking similar social media, PeerIndex also creates three subscores (Authority, Activity, and Audience) and one overall score. PeerIndex differs in its approach to best understanding and engaging your social network.

“We’re focusing on social impact and this idea of your topic graph: The subjects that you care about, the extent that those people in your networks care about those subjects, and what you have to say,” Azhar explains. “We show you what you talk about frequently, and the extent to which you resonate with other people on those subjects. We’re giving you a sense of your interest graph and how important you are in those topic communities.”

PeerIndex also offers one of Klout’s key features: Connecting similarly-minded brands and individuals.

“The people who have PeerIndexes, people active on the social web, are generating social capital, and they may be building it in ways that lines up with the company’s corporate mission,” says Azhar. “Now, we can tell you who’s likely to be a net promoter of your company, who’s likely to align very closely with the things your company stands for. A connection makes a lot of sense for you and a lot of sense for the recipient.”

PeerIndex believes bringing companies and their benefactors closer together can be mutually advantageous.

“What I’d like PeerIndex to do is to help make those connections happen more easily, and help people connect more, help people understand themselves more, and help people live their social lives better.”

“I was goaded into using Twitter several years ago by friends,” Peterson says. “I didn’t have a sense whether or not my use of the medium was having an impact. Being a measurement guy, I had to have some numbers. So I went out and tried some of the services… and I was really unsatisfied.

Twitalyzer avoids focusing on “more narcissistic measures of personal self worth and ego” and collects “hard data” in the form of Impact, Engagement, Velocity, Reach, and several other metrics, which allow you to understand how you use Twitter.

“We’ve given our customers the ability to take everything out of that metrics dashboard except the stuff that’s important to them,” says Peterson. “We have 30 metrics, but if you want to track your Impact, Engagement, follower count, and the number of unique people retweeting your message, you can just strip everything out of that dashboard and you can just look at those five metrics.”

Twitalyzer even allows you incorporate your Klout and PeerIndex scores, but this tool’s strength is allowing you to assess the power of each individual tweet, telling you which of your trends and topics are most popular.

“We’re aggregating these metrics so businesses can take a broad view and say, ‘What’s moving, and what’s not moving? Which of these metrics do we care about?'” Peterson says.

Other notable features include benchmarks, a way to compare your data with that of influential people you follow on Twitter, as well as subscription plans that offer special features like in-depth analysis, competitive account tracking, phone support, and API access.

“At first we were interested in customer service, and we found there’s really a lack of tools for people to do their jobs. Most times, their jobs aren’t super well-defined, ” says David Tran, co-founder of Crowdbooster, a Twitter analytics start-up based in Menlo Park, California. “That’s where we started.”

Tran, along with co-founders Ricky Yean and Mark Linsey, set out to “figure out how to help social media managers and community managers, actually define what their job is, and get better at it.”

“A lot of analytics give you nice graphs but you can’t figure out anything from the graphs,” says Tran. “With some tools, you only get that single score and you can’t figure out how you can actually increase the score and do better. That’s really where we wanted to hone in: How can we quickly show someone how well they’re doing and quickly tell them what they can do right away to do better?”

Crowdbooster—funded by Y Combinator—also focuses exclusively on Twitter, but its tracking service it also lets a user see the full reach of their tweets. It keeps track of your follower growth, top retweeters and your most influential followers. Your tweets are presented on a scatter plot graph, making it easy to view which tweets and topics garnered the most engagement.

Crowdbooster also recommends specific times during the day to tweet, based on the times your most influential followers are most active. To top it off, the program also allows you to schedule reminder notifications to tweet.

“Measuring numbers and bringing numbers up isn’t the endgame,” Tran says. “The endgame is talking to your loyal customers and helping out your brand.”

Take a Longview

Measuring online influence can be useful—and has potential to reinforce your social-media strategy (hey, it just feels cool when you get a high score)—particularly for growing brands looking to utilize technology to make their jobs easier and more effective. However, it’s not for everyone.

“Caring about raising your score, obsession about score, there’s definitely an element of vanity and ego there,” says Fernandez. “But this stuff definitely has a real impact on your life.”

“Businesses are used to measuring the effects of things they do in a digital medium, and Twitter is just another marketing channel,” Peterson says. “If you’re a person, don’t worry about it. Just use Twitter and have a good time. But if you’re a business, it’s just like everything else you do in the digital world.”