INTERESTING question.
Is the Wii a Fad?
imo no it isn't or rather it MIGHT not be.
if the wii sales plummets to say under 10k in a week or less. and new games stop being made for the system, then it will be a FAD, but until then the wii Cannot be a Fad.
Fad's have Definate Endings and until the wii has said ending, we cannot say it is a fad or not. if the wii dwindles yet remains a steady seller for over the next 2-3 years ..again not a fad. fads are shortlived products (short as it 1 maybe 2 years of "greatness" then bam "gone"..
magic the gathering was a fad- it is still around but no where near what it used to be- the peak lasted ~2 years
paper dresses were a fad -lasted a year or two
furby- fad- still around but it is not a "must have this product" item
Currently the PS3 is more of a FAD than the Wii is...
edit: expanding on that..
ps3 - hyped to all getout-
an initial must have release-shootings, thefts etc...
now extreme diminished demand for the product
that is a fad:
a temporary fashion, notion, manner of conduct, etc., esp. one followed enthusiastically by a group.