How can we find users willing to subscribe to our marketplace service?

You can use web sites such as Kickstarter to "pre-sell" memberships just like is done for other such products. For the "pre-sell", you may want to offer a special deal for being an early adopter.

There are also other sites, such as Fundable, that seek financing for the business.

Let me know if I can be of any further assistance.

Hey there! When I was building Partly Marketplace (an online aggregator and commerce platform for auto parts), we had the same general questions about acquisition. The problem with charging a subscription fee for tourist advice is that "Advice" is an on-demand type of product. Most users would activate your service and then go dormant after a vacation until their next trip. This would reduce the "value" users would see in becoming subscribers/customers. I would suggest sticking with the on-demand feel of Clarity for monetization.

To answer the big question of acquisition and where your customers will come from, that's a pretty broad question that has multiple answers.

Depending on your budget you can run targeted campaigns on Facebook to drive traffic. Since you're looking to mobilize travel bloggers, I would assume you have a few available to blog about your service, or perhaps you can share their articles to show off the experts your platform has. These are some pretty low-cost options. You should decide who your product is really for... Is it a younger generation of traveler where you're competing with Google? Or is it an older generation of traveler where you're competing with classic guides and research?

Once you know the answer, you'll be able to determine what's important to them and produce a service that fills their needs.

In short, your biggest opportunity is to reach out to your network of bloggers and get their support, since you'll need their expertise when the customers start to come.

If you want to chat about this or if you have any User Experience related questions, you should go ahead an schedule a call - I'd be more than happy to discuss this further.

Great space to be in! I have been working with a startup in the Medical and Tourism business (where people go abroad to get expensive surgeries done more affordably). It appears that advice from US Govt. agencies, free blog subscriptions, 'lonely planet' and others is quite aplenty. I would suggest that your true monetization lies in offering exclusive travel deals through partnerships with hotels, resorts, airlines and the like.
Free ebooks from your top bloggers may also be useful.

In sum - create an audience, gain their trust, give them a deal.

Happy to elaborate more on a call!