Selective Sync is a feature of the Dropbox desktop application that allows you to select only the folders you want to be synced to your computer. Selective Sync gives you the control to ensure you have only the files you need on any computer. It’s especially handy if you want to save space on netbooks and other computers with small hard drives.
To enable Selective Sync, head to your Dropbox preferences from your desktop:
Any folders you deselected will be removed from your hard drive, but will still be available through the website and on any computers linked to your Dropbox account.