The cryptographic integrity of MEGA's user data is important to us. We can therefore not allow you to distribute or make available your client application without going through us. We will perform a code audit of your product and promote/distribute it on our site. You will also receive a share of the revenue that your application generates.

So you do all the work and then you'll receive a share of the revenue?

I see your point, but to be fair they also promise promotion.

Whether it's fair depends, I think, on specifics of the product one builds using Mega API, and what's the potential there at all. An alternative client? Backup system using Mega as storage? Collaborative software?