Take a look at how other companies with similar problem resolved it, for example: AirBnB, Uber, TaskRabbit and others.

Every one of them, unless they were extremely lucky with timing, used a narrow geographic focus, approaching established communities and fulfilling demand for one side by hand for the first little while.

In your case you can approach established organisations like universities, churches, foundations, volunteer organisations and the like to get people that would do things and do exactly the same for the other side. Initially you need to do it by hand until it starts going viral.

Spreading the word through social media is great but it needs to be very targeted and approach people that can already find something in the application.

If there are other organizations that do similar postings, for example if there are requests for volunteering on Craigslist, you can approach them to have it posted in your application.

Narrowing on one geographic location is always easier in the beginning, because you can learn the area and all the players involved in the scene, and then maximise the output, expanding to new geographic locations when needed. It doesn't mean limiting your app, but just focusing your marketing efforts in one narrow location that can bring biggest output.

Everything that I mentioned above can be applied to offline and online social marketing. Unfortunately there is no magic solution to your problem except for bootstrapping it in the beginning and finding communities that you can leverage with biggest social impact return.

Good luck!
Denis.

I have recently launched my global consulting company (May 2014), as well as launching a one day event/expo for young entrepreneurs (Feb 2015). I am facing similar challenges regarding the exposure and creating awareness.

I have decided to give my website a face lift, work with a company to push emails out, and also attend 5-10 networking meetings per week in the metro area where I live. I have joined several local business associations, networking groups, and post very targeted industry information on social media. The data base that I have built is just short of 1,000 contacts. These contacts are all accurate. I usually generate 15-20 strong contacts per meeting. I have an open rate of 37% on my email campaigns and the web site has generated over 198,000 impressions in 6 week. Not a lot for the more established industry gurus and sites, but I am pleased with it.

I really work hard on the community connections. This has worked well. Now, after about 8 weeks of activities, my project is known in the metro area. All of my sales and 5 domestic and 4 international start-up clients are a direct result of these activities.

You might want to consider presenting in local Meetup meetings. We have a Tech Village here in Atlanta and the networking meeting draws about 400 people. I am very selective and prepare each and every of the networking meetings one or two days in advance.

I know that it is time consuming and not everybody believes in face-to-face networking like that. It works for me.

Call me if you have additional questions about networking and my results.

I would suggest launching in certain geographical locations ONLY.

Kind of like how Uber does it.

An app like you're describing is pointless if it's value comes from location based services.

Push one small geographical locations through marketing tactics that will bring people to your app download page. Think of localized contest in which the prizes have something to do with the location (major league baseball tickets, for example).

If someone attempts joining from a different location, inform them you're launching soon and keep their emails on file.

This then tells you where the most demand comes from, and give you a good idea of the next location to "open".

This also allows you to test what is working and what isn't because your app will be used by people as if it were already popular all over the world.

Yours is a Geo location based app, I understand.

There are many ways to penetrate your market. First, you need to segment your market into different verticals on the basis of the factors like age, interests, gender or location.

Once they are segregated, you have to design specific marketing campaigns catering to each category, focusing on number of sign ups and a great experience.

Such campaigns can be run both online and offline.

This would gain you both PR and aggressive Sign ups.

Don't follow anyone, make your own story. All the best!

In case you need help making the campaigns and measuring the ROI, feel free to get in touch. :)