Just came across the below description and warning on an Aussie Site which I am sure won't mind me sharing/advertising their link:

http://www.gadgetguy.com.au/dropbox-scam-making-the-rounds-heres-how-to-work-out-whats-fake/

This is just the standard, run of the mill email Phishing attack.

Here's another article:

Dropbox used for convincing phishing attack

PCWorld - Oct 19, 2014 5:00 PM

Dropbox’s file storage service was used for a tricky phishing attack, although the service was quick to shut down it down, according to Symantec.

“The email claims the document can be viewed by clicking on the link included in the message,” wrote Nick Johnston of Symantec in a blog post. “However, the link opens a fake Dropbox login page, hosted on Dropbox itself.”

By hosting the fake login page on Dropbox, the scammers gain some benefits over hosting it on a random, strange-looking domain name. The phishing page is contained within Dropbox’s user content domain, similar to shared photos or files, Johnston wrote.

Well now, that's a little more serious.

I don't know why people click on these links. Why do they think that some stranger is sharing a file with them?