Basically, a chair ususually used by
a
geek, nerd, or gamer designed for
sitting long durations in front of a computer.
The "fart" comes in because typically
the padding in the chair retains the
residual flatulence which is outputted
into the chair over a long period of time by the owner.
Often times an IFC will also have holes
or other defects in it, sometimes an
arm missing, torn/holes in fabric, etc, but despite all the damage and/or smell,
the user will typically keep an IFC around until the chair starts to
deteriorate to the point of being
unuseable.
Cloth-padded chairs tend to fit the IFC
profile more perfectly since leather tends to make the fart smell "bounce off" the chair instead of getting trapped inside the padding. A true
internet fart chair may even retain the
fart smell for years.