How to fix URL links that no longer function for Google Drive (Google Docs) file hosting and sharing
17Here is some important information for anyone who uses Google Drive or Google Docs for file hosting and file sharing purposes (essentially those who use the cloud storage to make files accessible to others). If you've used Google Drive prior to July 2013, the URL links to your files that were used in order to share these files with others have changed. Anybody who has and tries to make use of the old links will not be able to download your files anymore. Now, all docs.google.com file sharing links must now end with the suffix /edit?usp=sharing instead of just /edit in order to access the files in question. By adding this bit of information to the end of your previous links, this will allow your previous links to still function and others to be able to download your shared files as intended.
UPDATE May 29, 2014:
Also, any URLs that used to point to docs.google.com now have to point to drive.google.com in order to allow access to the file in question.