There, you can select the folders and files you want to sync to your computer. Just open your Dropbox preferences, select the Account tab, then click the Change Settings … button beside the Selective Sync entry. If you need some extra space, you can use Dropbox's Selective Sync to store only your most important files on your computer.
With online previews and Office file editing online, you might find that you need fewer of your Dropbox files actually stored on your computer. Plus, as you work on the file together in Dropbox, the online preview will update so everyone always sees the latest version.
It's an easy way to keep the conversation about your files in the same place, so nothing gets lost. They'll get a notification in Dropbox or their email inbox, and you'll see the comments appear in real-time as they're added. Type out your comments, and add your colleagues' names with an symbol to mention them in a comment. Select any file, or open it in the preview tool to see the sidebar with the comments. You can find this feature on the web and mobile version of Dropbox, and in the desktop app (not your system file browser, the actual Dropbox app).
