Assuming you are using Git, that means every developer you employ is running around with a complete repository history of your source code on their laptop. They probably also have internal documents regarding design, product management, etc. Many of them probably use a cloud backup service like Mozy/Dropbox etc. I don't think Github is the weakest link in this chain.
That aside, source code is typically far from your most valuable asset, especially if you're a SaaS offering like many startups. What could a competitor do with your code, absent your people and your branding? Even if it were, Github would probably be the least of your security concerns.
We're a startup and we house all of our code on Github in private organization repositories.
Yes, I use Github for all projects, both open and closed source. Their infrastructure isn't something I can easily duplicate, and it's nice knowing my code is safe "just in case" (especially when I might be the only developer on the project, hence no other checkouts of the repo).
AdTaily does. I think startups wouldn't make much progress without hosted services like github. Hosting everything from source code, through email, to documents by ourself would consume much of our time and money so important especially at the very beginning.
We do. With a team scattered across Asia and Europe, using Gihtub to host our project do make sense. And I don’t see how it would be possible to be as efficient without this tool! Now, regarding the issue of confidentiality, I don’t see any problem.
As stated by Joseph Ruscio, the code is not the only component that makes a startup. What about the months spent on SEO, marketing, recruiting, financing?