And if you wish to get a taste of how much work Dropbox is doing to achieve their simplicity, spend some time using (the competing) Box.
Clients that recognise the extra metadata can vastly improve the UI for notifications. Older clients continue treating it as regular email.
Re: last tweet, high time for an open standard / protocol built a-top emails for handling things like notifications.
@rashmiswamy Thanks Rashmi, and Happy B’day to you too!