If there is not enough incentives or a way to make them visible to the right crowd, it could generate a lack of contribution by the crowd. Even if this issue could be solved following some crowdsourcing platforms and best practises behaviour or documents, it is a factor that should be taken into account.
It is highly discussed the fact that several jobs that were done by professionals are now done amateurs and people without experience that make part of the crowd. It has reduced the wages of professionals in fields such as design and creative jobs. Other related problem is the possible damage of some brands that have been accused to have this behaviour.
As there are no written contracts, non-disclosure agreements, or agreeable terms it is not possible to assign responsibilities if any problem arises and in some other cases it is difficult to maintain the working relation until the end of the project.
Even if this is one of the main advantages of the crowdsourcing, it has been seen that it doesn’t always produce quality results. This is mostly guided by some lack of visibility or insufficient incentive to motivate the crowd.
You could find some other critics about crowdsourcing. What it is real is that Crowdsourcing and all its strategies have come to remain. That’s what the last marketing campaigns have shown through crowd voting and crowd creation, association through crowd funding and other initiatives through crowd wisdom.