No one excels at everything. As much as you may be the authority of your main product or service, and be passionate about it, chances are your messaging leaves something to be desired. Or perhaps promoting your offerings isn't your thing. Maybe you struggle with selling your products or services. On the flip side, prospects or strangers may want to pick your brain about specific advertising, marketing, or PR advice. Either way, the hours of the day are finite and intrinsically valuable. As you give or receive free advice, is it possible to quantify-to put a concrete number on-the time being used? To say not just, "your/my time is valuable," but "that's [insert dollar amount] of your/my time."

It turns out the answer is yes. And to do so, you need only use the social startup 12ish. The Indianapolis, Ind.-based platform that launched in April allows you to bill your time in 12-minute increments.

To sign up, you can connect your PayPal account to your user profile and set up topics on which you're willing to share your expertise. Then you set a billing rate for a 12-minute conversation. People can see a calendar you share and book time with you to "tap your mind" at the rate you've defined. You don't even need a full-fledged 12ver account. You can also create an account with just an email and password (skipping PayPal setup, Twitter login, etc.), which is part of the easy checkout process. It's only required that you have a touchtone phone for a 12.5-minute, voice-to-voice conversation (though you can book multiple slots for longer conversations). The platform pre-authorizes customers' credit cards when they book their calls as well as keeps phone numbers and email addresses hidden from both parties. To profit, 12ish charges a transaction fee of 10 percent, plus a $1 connection charge.

"Every one of us is interesting, and social media just skims the surface for bringing that out into the collective," says 12ish CEO and co-founder, Colin Mathews. "Being able to tap into someone else's wisdom and experience at a very personal level could intensely change how we improve our lives and even how we view ourselves. 12ish was built to do just that. In the same way that 140 characters made sharing approachable and digestible, we think a 12-minute conversation does the same."

If you're a community manager, for example, you may set $7 for users to chat with you for 12 minutes on all things content creation. Say you've just started a job as an entry-level public relations coordinator. What are the pitfalls and strategies? For $10, you can chat with a senior public relations professional who is happy to share her experience, approaches, and philosophy on PR.

"It's really easy to carve out a couple of hours a week to bring in some extra money and talk about things that excite you," says Mathews, who has been a software engineer for more than 15 years. "Some people will use 12ish as a way to generate leads for an existing business. Some will slowly turn a hobby into something more. Some will use 12ish as a teaching platform. Some will use it just to engage with people on topics they feel passionately about."

Other people have booked veteran travelers for tips on getting around with young children in tow, job recruiters have helped people polish their resumes, and people have given software development and design guidance. People can even book others to be a listening ear when they're feeling upset or angry. In case you want to review the conversation, a recording of each call is made available to both parties after the call has ended. Reviews help people decide which 12vers are offering the best consultations.

While the startup is about having personal conversations on any topic with no limitations on what you can discuss, Mathews says the No. 1 topic so far has been people seeking and giving startup advice. "That's largely a function of who we've approached to become early adopters, so that's not meant to be indicative of where I see our future," says Mathews, who has been booked on 12ish to share his startup experience bootstrapping, moonlighting, pitching, raising investment, and enduring psychological challenges along the way. "I've been booked, for instance, to help validate startup ideas and to offer suggestions on what next steps a founder should take with their business."

Long-term, Mathews says he hopes to see people making their living as 12vers, and that it's top of mind when you're out in the world and want to learn more about something. "12ish gives people a way to get a deeper understanding of the world around them," he says. "Now when I'm watching a documentary on the moon landings, I find myself wanting to book someone from mission control to get a glimpse into what was going through their heads. When I'm ordering a beer, I want to book someone who brews beer at home. I want a basic understanding of the Higgs particle discovery without doing hours of research on Wikipedia."

In terms of development, Mathews says 12ish is continuing to improve and tweak the experience in response to users' needs. They're also building out ways to find and browse 12vers, embed 12ish on users' websites and blogs, etc., and become bookable directly from their own site.

"I was worried that people who booked me would be really hard on me or would be rude or indifferent," he says. "Nothing could be further from the truth. The people I've had 12ishes with have been incredibly friendly and genuinely interested in our conversation. I guess that's the great thing about people paying you for your time, even if it's only $1. The trolls of the Internet aren't interested in spending money."