Instead of finding a link — then sharing it — Messenger now supports direct sharing of Dropbox stuff. You can add a video, picture or text document, so long as you have both Messenger and Dropbox on your phone.
In a conversation, just tap the ‘More’ button to see the new Dropbox interaction. Once selected, a menu of your Dropbox files will be available for sharing.
Facebook says the feature is rolling out incrementally, so if you’re not seeing it just yet – sit tight.