How is Dropbox's Mailbox app any different from LinkedIn Intro app?

I was having a drink with a friend, who saw me use the Dropbox's Mailbox App. After explaining him how this thing worked, I realized that the mechanism is not so different from LinkedIn's Intro app, which has been bashed and mashed around for it's privacy implications.

Then I asked him a question: how is Mailbox any different from Intro?

Here is an except from Mailbox's website:

In order to deliver email as quickly as possible, send push notifications, and keep an accurate badge count on your home screen, Mailbox checks your email from the cloud.

It does not seem to be too different. The biggest difference I see is in the press -- mainly company's track record. But then again, Dropbox? LinkedIn? It's a seesaw of privacy policies and practices, deteriorating little by little on each side (not to say that these are the only companies).

It is a fact that some of my close friends have begun deactivating their LinkedIn accounts. Is it a matter of time until people stop using Mailbox? stop using GMail all together?

Needless to say, Mailbox is a quality app, and I will probably not give up using it for a while. I love the app. But again, I ask the question: how is Mailbox any different from LinkedIn Intro app?