For technical reasons, we have temporarily closed the sign up for new user, in preparation for launching the phase 2 of the preview program.
If you are an existing user, this closure does not affect you. Your service continues as normal and you can log in, as usual, to back up and restore your files.
We are currently working on phase 2 of the preview program, with some fairly exciting new features that we hope to announce shortly. The phase 2 preview program will be launching in April.