It's a pedantic note, but I agree they should clarify on their project page that in the event of server compromise only your past data is secure and only if no one accesses past data post-compromise. As usual, encrypt offline with your own unshared private key if you really want it to stay private. I agree with the comment at the top though that the primary utility is the legal predicament it presents.
Computers with dotjs or greasemonkey could also sneakily get your stuff, being all the compromising code invisible in network traffic and even inspecting the page source. Something to consider if using an untrusted computer (and not just keyloggers and the like).
