On Thursday January 19, 2012, Megaupload and its sister sites were closed due to allegations that its founder and its other executives were in violation of “piracy” laws.
Content gets removed all the time.
Keep it safe by downloading. Access it offline.
Here is how
Download from Youtube with KeepVid (or many other applications, addons and plugins).
Also backup your own data!
Buy an external USB hard drive and copy your most valuable data there (eg. personal photos, documents and projects).