I've always found it a pain that Dropbox doesn't support syncing to multiple accounts at the same time, e.g. to my work account as well as to my personal one.
Of course, I could share the contents of one with the other, but I only have a free Dropbox account for my personal files, and I like to keep work and personal content separate.
After some Googling, I came across this blog post by Daniel Mann that shows you how you can sync multiple Dropbox accounts to your Mac:
The gist of it is that you simply run two separate Dropbox instances at the same time using the Automator to run a shell script:
HOME=$HOME/Dropbox-personal /Applications/Dropbox.app/Contents/MacOS/Dropbox &You even can setup your Mac to automatically run the Automator .app in your System Preferences > Users & Groups > Login Items.
Check out Mr Mann's blog for step-by-step details on how you can set up multiple Dropboxes on your Mac.