While I was searching for how to fix my missing Dropbox contextual menus yesterday, I came across these handy links:
If you're a Path Finder 6 user, Thanh Pham has figured out how to make an Automator service that will let you share a public Dropbox link from Path Finder's contextual menu. More often than not, I find that I need to share files that aren't in my Public folder already, so I don't know how much I'll use this, but it's handy to have a bit of Dropbox integration in Path Finder nevertheless.
Bloodrop is a Dropbox droplet that I might find slightly more useful. Simply add the droplet to your dock and then drag any files you want to share on top of it. Bloodrop will copy those files to your Dropbox public folder and place links to those files in your clipboard. Easy peasy.