We recommend that you proceed with caution. Crowdspring strongly suggests that you keep all transactions (including file exchange) on crowdspring.
We have tools in place that help protect your intellectual property and interests. Of course, you can develop relationships with the clients you meet here and profit from future assignments and follow-up work, but, during a current open project it's risky to stray off the site. And you can always help clients in the future through a 1-to-1 project where you work directly with that client.