Crowdfunding by the legal standards of the term CANNOT give a percentage of the profits ~ and this is exaclty what these sites promise.

@Kevin Dawravoo, from where I sit, your net "cash flow" (per month average) divided by "the amount of money you have put into the property" IS your Return On Investment.Of course, when you are analyzing any potential deal, all income and expense amounts are "mythical" to some degree - the trick is to become a good guesser, and there are plenty of available tools to help.The overall value of the property is perhaps the least relevant figure here, except as it relates to your tolerance to RISK in calculating your borrowings as a percentage of the actual property value.

Others say you just take the percentage you contribute and 10% for managing it. 

Make 20 offers and you'll get 1 deal done (my percentage now is higher because of experience but 5% closing ratio is about right when you're starting out).

Not big money, but with very little money out of your own pocket, the percentage returns should be astronomical.You haven't said a word about operating expenses as a buy and hold nor rehab costs to get the property to "safe, clean and livable" (which normally will be well below the cost to make a property marketable for retail sale.)

Does anybody know percentages of clients that disappear vs actually buy?

There's 2 simples ways to protect yourself.1) Draft up a general "Marketing agreement" which should say something along the lines of, everything that I bring you I will get X (flat fee or percentage, your choice).2) You could also get the property under contract yourself and "assign" your contract to him. 

They had divided interests among multiple businesses.Finally I decided to buy an office building and hire a full time employee that does nothing but work on my business all the time.I set a salary paid every 2 weeks and then a bonus structure of a certain percentage of income for my commercial real estate transactions.

The more offers you make, the more deals you find, and some percentage of those end up under contract and surviving due diligence.

what percentage down did they offer you?