Update as of 20 Nov 2016: for some reason the Wiki is still available and the notice is gone. I wonder why. Regardless, you still have time to make a local copy of the portal, which is a good thing. Uhm... Thank you, AD?.. (-_-)ゞ
Just an FYI for all XSI-zealots like me out there.
Autodesk decided to stop hosting the Softimage Wiki portal due to... Well, who the heck cares anymore? I guess it's too expensive for a large international company to host a couple of gigs of files. At least they had the courtesy to warn us beforehand.
Anyway, there you go.
So if there's something you need from the portal you better make a local copy before Nov, 11.