I have worked on several projects that have had too many partners in the venture. For example, someone providing the content, someone else creating the software, someone else selling it and someone else promoting it.
There are usually problems when there are too many partners. First of all, there are far too many parties to create a sensible profit for everyone. Secondly, requirements and changes to the project involve too many people and more time is spent communicating ideas than implementing them.
More often than not, there’s one or more ‘sacrificial’ parties that agree to make no money, perhaps as a trial or for a limited time. This never works. Everyone has to get something out of the deal otherwise people back out and the whole thing collapses.
Too many partners also results in solutions that lack direction. Everyone and no-one owns the requirements, misunderstandings happen, sometimes issues are ignored and projects close due to reasons that could have been prevented.
In summary, try to limit the number of partners. Consider paying upfront for something rather than having a revenue share. If there are too many parties taking a revenue share then don’t even start the project. Only consider partners doing ‘something for nothing’, if they are gaining something else such as publicity or shared customers for other products.
If there really has to be lots of parties, make sure one has overall control and owns the project. Put processes in place to encourage quick and easy decision making while avoiding many cross-party meetings. Also think about having alternative suppliers/partners to minimise the risk of one of them pulling out.