We are looking to create a crowdfunding platform (donations-based). What things should we consider on the compliance side?

Check out https://www.balancedpayments.com/ They are made for marketplaces. Airbnb CEO among others invested in them and they have some of the best pricing/payout fees. Also some good info on http://www.collaborativeconsumption.com/2013/10/08/online-marketplaces-are-hard/ One of Balanced Payments co-founders is writing this blog series on marketplaces.

Your support software should cater to your needs, depending on how your business operates. Fiver uses Vanilla forum and Zendesk. Thumbtack uses Zendesk. Not sure about AirBNB, their help center seems to be custom. Depending on how well funded your are, I would recommend starting with a free plan with one of the help desk SaaS products, or even using open source ticketing platform. Then, as your needs grow and you need integration with your marketplace, there's no reason you can't scale and migrate.

It's all about building a relationship with these journalists and bloggers. You want them in your pocket long term. Ultimately, they are usually interested in the same things as you, which gives you a chance to connect on a deeper level and make an online friend. If you make a friend, then maybe they can even introduce you to their other journalist friends when the time is right. Ps: when you finally do send them your stuff, keep it short and make sure your visuals get the point off without them needing to read a description. Visual storytelling is huge. Remember: people don't like to read

It depends on a number of factors but I'd boil it down to two key things to start: 1) What is your real cost to provide a free plan or trial? 2) Who exactly is your customer and what are they used to paying and who and how do they pay today? When you say "online workforce marketplace" it sounds as though you're placing virtual workers. If that's the case, or if you're paying for the supply side of the marketplace, the question is how much can you subsidize demand? Depending on where you're at in the process, I'd also question how much you can learn about the viability of your marketplace by offering a free version, assuming again, that free is actually a real cost to you. I was part of a SaaS project that started charging people for early access based mostly on just a good landing page (we clearly stated they were pre-paying) and were amazed at the response. I've also run a SaaS product that offered free trials and realized that the support costs and hand-holding and selling required to convert from free trial to paid wasn't worth it, this despite the product's significant average ARR. You might be better off providing a "more information" sign-up form (to capture more leads) and let them ask for a free trial while only showing your paid options. I've been amazed at the lead capture potential from a simple "have questions? Click here and we'll contact you" This is all the generalized advice I can offer based on the limited information I have, but happy to dive-in further if you'd like on a call.

Apps are difficult to fund on IndieGoGo as few are successful, and we rarely take them on as clients. Websites like http://appsfunder.com/ are made for that very reason, but again, difficult to build enough of a following willing to pay top dollar for an app that could very well be free, already existing in the marketplace. A site that is gaining more traction you may want to look into would be http://appsplit.com/. Again, Appsplit Is Crowdfunding For Apps specifically.