What is the pros and cons of a marketplace website like houzz.com, zillow.com and trulia.com where users send mail to professional without logging in?

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.

It's very important. (first, read this article by Josh Breinlinger - http://acrowdedspace.com/post/47647912203/a-critical-but-ignored-metric-for-marketplaces) The way you achieve success in a marketplace is by driving liquidity for both your supply & demand. Demand-side Liquidity = When users come to your marketplace, they can achieve their goals. Supply-side Liquidity = When supply comes to your marketplace they can achieve their goals... which are almost always to make money. If you're making a large amount of your supply-side users a full-time income, then you're helping them achieve liquidity. Now it's not so black and white and it doesn't always have to be a "full-time income." It depends what their goals are. E.g., 1) At Airbnb, renters aren't looking to quit their day jobs and become landlords full-time... they're just look to earn a substantial amount of income to offset their rent, mortgage, etc. So in this case, I would probably goal on # of renters that earn >$500 / month... and (in the first 1-5 years) try to grow this number by 10-20% MoM... and maybe by just 5% once you're in the mid-high tens of millions in yearly revenue. 2) At Kickstarter, the goal of the supply-side is to get their project successfully funded. They don't care if the project creator is "full-time"... they just want to make sure they meet their funding goal. This is why they talk about their 44% project success rate all the time - http://www.kickstarter.com/help/stats 3) At Udemy, our instructors want a substantial amount of their income to be driven from their Udemy course earnings... so we look at how many instructors are earning >$2k / month.

You would include all those lines in your revenue. Typically this looks like: Receipts: [full cash inflows] Fees: [payouts to vendors] Gross Receipts: [subtract] This ALL does into the Revenue category, so that your stated revenue is indeed net of fees, but you can see how it breaks out to understand how money is moving. That's if the margin there is very slim. If the margin is pretty good, and if you believe you can increase that margin materially over time, you can consider putting those fees into your gross margin instead of in your income.

I think you're looking at this the wrong way. Your customer acquisition cost is not something you should benchmark against other businesses. Without knowing more, like your short and long-term goals, it's impossible to answer. Two companies with similar business models may have different answers to this question. A venture-backed startup trying to keep up with aggressive revenue goals may be able to stomach an astronomical CAC. A bootstrapped startup that is not seeking venture money may aim for slower growth and much lower CAC. I suggest setting up a call with a marketing or finance expert to determine what CAC is appropriate for your company and how to get there.

I like to separate your question into 2 sub-questions: #1 How do we determine which side to charge? #2 How much is the right amount to charge? On #1, my answer is that you can charge the side(s) for whom you add the most value. In your examples, Uber really solves a big problem for drivers, it's that they sit idle for a good part of the day, so are willing to pay a lot for new leads. (their alternative is no work) Consumers are charged more for the convenience of a private car but they are probably not so much willing to pay more for a taxi, even if they can hail one from their phones. For AirBnB, it's a mix, it's a way for landlords to monetize idle capacity which they are willing to pay for, but it's also a way for a renter to pay less than they would normally pay for a hotel. On #2 (how much), I like to triangulate a number of factors: - What's the maximum amount I can charge one side, while still being a good deal for them. - How much do I need to charge so that I can become profitable? (the economics are quite different if you charge 3% vs. 12%) - What are comparable services charging for substitutes/competitive offerings? I will just add that there is no formulaic way to determine pricing strategies (curated vs. open), and it's a lot more about what's the comparable and what the value delivered is. That's how I approached the question while deciding the business model at ProBueno.com (my startup)