DropBox vs Google Inbox

Dropbox is a Web-based file hosting service that uses cloud computing to enable users to store and share files and folders with others across the Internet using file synchronization. There are both free and paid services, each with varying options. In comparison to similar services, Dropbox offers a relatively large number of user clients across a variety of desktop and mobile operating systems. DropBox alternatives for enterprise are: Box, Microsoft SharePoint, Office 365.
Google Inbox
Inbox by Gmail is a new app from the Gmail team. Inbox is an organized place to get things done and get back to what matters. Bundles keep emails organized.
Face to face in the news:

2016 - Google Inbox now helps you track calendar events. DropBox keeps calm

Google is launching an update to it's Gmail-based app Inbox. The most interesting new feature is that Inbox can now help you keep track of events and the emails you send back and forth about them. This feature is linked to Calendar invites, similar to how trip bundles are triggered by hotel or flight bookings. Google tells me this is based on the same technology that powers Inbox’s trip bundles, which pull all your hotel, flight, restaurant and car reservations into a single, shareable bundle.

2015 - Dropbox is shutting down its email app Mailbox to strike back at Google Inbox

Dropbox will shut down its popular email app Mailbox on Feb. 26, 2016. The reason for closing was vague. Dropbox CEO Drew Houston and CTO Arash Ferdowsi called the decision the result of "tough choices" in a blog post announcing the news. "Over the past few months, we’ve increased our team’s focus on collaboration and simplifying the way people work together. In light of that, we’ve made the difficult decision to shut down Carousel and Mailbox." The company says it will be "using what we've learned from Mailbox to build new ways to communicate and collaborate," pointing to its note-taking app Paper, which rolled out in beta earlier this year. Mailbox was already hugely popular when Dropbox acquired it in 2013, but had been struggling to deal will the massive influx of users. It really took off after the startup was finally able to do away with its waitlist — which at one point was hundreds of thousands of users long.