Symantec recently detected a large number of phishing emails that were telling users someone had sent them a large file, with a link to a Dropbox page - or so it appears. But it turns out the link opens in a page that looks like the Dropbox login page, but it's a fake. However, it was hosted on Dropbox, so the URL looks right. This one has been shut down but be on the lookout for copycat attacks that use the same method with online file storage services.
Read more about it here: