Dropbox doesn't update

Explained here
http://simonhackett.com/2013/04/05/dropbox-sharing-doesnt-work-and-the-fi/
When a link is shared it is for a "snapshot" of the content at that time.


Ie, the originator shared a link rather than the folder
Here's the basic instructions
https://www.dropbox.com/help/274/en
and
https://www.dropbox.com/help/19/en

and the Invite screen
https://www.dropbox.com/help/213/en


Note, also. if you join a shared folder, the content size will count against your quote.
Will joining someone else's shared folder use my quota?
https://www.dropbox.com/help/59/en

This article confirms, when someone shares a "nearly" 2G folder, your quota will be about used up!
http://www.pcworld.com/article/2032507/the-simple-practical-way-to-share-a-dropbox-folder.html


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Security (non) of the referral system, from 10/2011
http://www.zdnet.com/blog/bott/sorry-dropbox-i-still-dont-trust-you/4173