I can speak in general to the marketplace business model (re: Gun.io -- we have 20,000+ on the expert side) and tell you that the conventional wisdom in a marketplace model is that you must first subsidize the supply side of the market, which is then used to attract the demand side. Think of a shopping mall as a standard example: must have stores before shoppers, but how do you overcome the chicken/egg? The answer is you have to get big box stores to "anchor" the model and then get smaller stores to fill in the gaps. All of that must be done first, by demonstrating to those stores who you WILL attract market demand after you have them in place via your marketing efforts to the demand side.

Just being on Clarity I have received probably a dozen requests to join another "experts" marketplace. That's not going to cut it because it's obviously a copycat model. The key is going to be targeted outreach whereby the experts see a legit way to grow their businesses and their brands by being involved.