Take this website for example. You'll see a lovely picture and a usage of "viewn". Now, what's interesting to note in this example is that the usage appears to be from a native german english speaker (note the ".de" extension on the URL).
Also, I'm no expert computer programmer, but you'll notice if you check out the search results that many of the URL extensions contain a "viewn" modifier such as the one in the URL above.
Maybe someone more adept at programming could enlighten us, but I suspect it's actually "viewn" and not, say, "view N".
The moderater on this board (which seems to have something to do with an internet radio station) demonstrates what I'd conjecture is the most common usage of "viewn".
Under no circumstances should this station be viewn as an opportunity to go off on a tangent and play only things you like.
"Viewn" amounts to basically a passive form of "view" and the two seem function as a pair much like "see/seen", "show/shown", "tear/torn" "grow/grown" or "shear/shorn". In an impromtu test of my roommates just now, I asked them to construct a sentence in the passive voice using to verb "to view" that functioned as a caption that explain what on was looking at in a picture of the Empire State Building from the top of the World Trade Center. One roommate didn't react at all, but the other said "you want me to say viewn, but I know that's not right."
Interesting! Here is one other potential candidates for the "viewn" treatment (unforunately the only one I can think of):
Shoon (Shoo) - "The rat was shoon from the house."
Can you think of any more?