I don't think this can be considered vendor lock-in :) You are probably way more "locked-in" by your language or framework of choice. Plus, you can always download the environment into your local machine and forget about Cloud9 at any time when it doesn't fit your needs anymore.
Have had many hats on in my life: Developer, Team Lead, Scrum Master, Architect and Product Owner. Now back to developer \o/ Interested in product discovery, quality assurance and language design.
You are about to bind your development environment to a single company. Do you want to continue?
[yes] [no] [cancel]
I don't think this can be considered vendor lock-in :) You are probably way more "locked-in" by your language or framework of choice. Plus, you can always download the environment into your local machine and forget about Cloud9 at any time when it doesn't fit your needs anymore.
People have been doing that with Microsoft Visual Studio, NetBeans, etc. for ages. I don't think that a cloud IDE is any worse than that.