WSJ:

He said Dropbox will keep the Mailbox service running as a stand-alone app, and over time Dropbox will also use Mailbox’s technology to enhance Dropbox features, like email attachments.

Good or bad? But, I suppose the lesson is, if you want your startup to be acquired, build an email application. Sparrow didn’t last long either. Will have to make sure my MAIL app is back on the home screen.. .just in case.