Basically they gain the fey charm, grace, some powers.. the fey sub-type etc.. Plus perhaps a natural disposition to whatever is normal behavior to your fey ancestor.
To my knowledge, Fey do not have cynosures, require to follow the fey laws, and cannot crux. Mostly because they aren't immortal like the fey.
The Children of the Fey book holds a bit on this.. It classifies the race as Feyborn however. Though it's largely the same thing. All of the following is taken from Children of the Fey p. 2,3,4
Given the racial traits listed, I think it's safe to assume that Feytouched and Feyborn are as similar as it's possible to get.
Feyborn Racial Traits wrote:
· +2 bonus to Charisma, -2 penalty to
Constitution. Feyborn possess powerful
personalities and a strong sense of selfawareness,
but they are frailer and weaker than
normal humans.
· Medium: As Medium-size creatures,
Feyborn have no special bonuses or penalties
due to their size.
· Feyborn base land speed is 30 feet.
· Low-Light Vision: Feyborn can see
twice as far as a human in starlight, moonlight
and similar conditions of poor illumination. He
retains the ability to distinguish color and detail
under these conditions.
· Spell-Like abilities: A feyborn with a
Charisma score of at least 11 may choose one
of the following abilities: 1/day – charm
person, 1/day – disguise self, 1/day – entangle
or 1/day – faerie fire. Caster level 1st; save DC
10 + feyborn’s Charisma modifier + spell level.
Once chosen, this ability cannot be changed.
See the spell descriptions for more details.
· Add +1 to the Difficulty Class for all
saving throws against enchantment spells cast
by the feyborn. Their innate connection to fey
magic gives them a talent for beguiling others.
This adjustment stacks with those from similar
effects, such as the Spell Focus or Fey Sorcery
feat.
· Automatic Languages: Common. Bonus
Languages: Draconic, Elven, Gnome, Sylvan
and Goblin. Feyborn learn the languages of
many creatures that inhabit their forests.
· Favored Class: Bard. A multiclass
feyborn’s bard levels to not count when
determining whether he takes an experience
point penalty.
Quote:
Adulthood 15 Years
Barbarian, Rogue, Sorcerer +1d4
Bard, Fighter, Paladin,Ranger +1d6
Cleric, Druid, Monk, Wizard +2d6
Middle Age 60
Old 100
Venerable 150
Maximum Age +2d20
Height and Weight
Male 4' 8" +2d8 | 95 lb. × (1d8) lb.
Female 4' 4" +2d8 | 70 lb. × (1d8) lb.
The Feyborn wrote:
The feyborn are the product of mortal parents
whose blood contains some tinge of fey magic.
Many are born to mortal parents, although their
ancestry may be tinged by a great-grandfather
cavorting with a dryad, but some are the result
of a powerful blessing from a fey creature of
great power while the child is still in the womb.
The favor of a fairy is a powerful thing, and
their good will towards one who is not yet born
can have a powerful effect on their blood and
destiny.
The feyborn are marked with strangeness,
right from their moment of birth. There is
something strange and magical about them even
when they lie in the cradle, their mis-matched
eyes changing color with the shift of the winds.
As they grow up, they exhibit an even stronger
affinity with fey magic, possessing a natural
way with the plants and animals of the woods
and occasionally exhibiting some outward flash
of fey magic.
Feyborn are more at home in the wilds of
their fairy ancestors than large cities. Many
suffer torment and ostracism at the hands of
superstitious villagers that fear their fey nature,
while others find the touch of fey-blood a
blessing as they grow into maturity. From a
young age, they exhibit a strong connection
with the natural world and magic, and many use
their skills to play practical jokes and tricks on
those that surround them.
Even the most erratic and fun-loving feyborn is
influenced by their deep connection to nature,
and although they may seem like a shallow
nuisance to those around them they are also
prone to flashes of sudden depth and insight.
Physical Description wrote:
The feyborn’s physical
features are as diverse as the mortal stock they
are born into, though they are usually slender
and possess a few fey traits. Eyes of two
different shades are common, as is having one
arm or leg a few hairs longer than the other.
Some feyborn exhibit traits that are
associated with their fairy ancestors – a green
cast to the skin if they are descended from a
dryad, furred haunches or a small tail if they are
descended from a satyr, or elven features if they
are related to pixies and similar small folk.
Feyborn always seem younger than their
years, and they are known to age slowly. They
retain their youthful features well into their
forties and fifties, and even in their dotage they
have the features of humans only half their age.
Regardless of their personal magnetism and
charisma, all feyborn are considered fair to look
at by humans and other demi-human races.
Their alien beauty often wins them admirers as
quickly as their mercurial temperament drives
others away.
Relations wrote:
Most feyborn are communal
creatures that love interacting with others, but
few maintain a strong connection to the human
communities that raised them. Their long life
and strange outlook often sees them leaving
their homes at a young age, and many drift
towards communities of other forest creatures.
With their love of woods and forests and a
strong affinity for fairy mischief, many feyborn
find themselves associating with true fey and
gnomes. More serious feyborn can be found
living among forest-dwelling elves, and some
drift to communities of outcast half-breeds
along with half-elves and half-orcs.
Alignment wrote:
With their strong connection to
nature and their affinity for the cyclic nature of
life, many feyborn tend to be fairly neutral in
their view of the world. While some may drift
towards mischief and randomness, and others
adopt a fundamentally moral outlook on the
world, they are rarely swayed far in either
direction. Although they are rare, a few feyborn
turn to evil as a result of the ostracism they feel
in their youth or their link to a darker strand of
fairy blood.
There is quite a bit more on them all as the book are a few pages long. The lore added in that book seems to be somewhat similar to The Complete Guide to Fey, in that the races are wildly overpowered thanks to some of the feats, spells and so on. . . . Then again, the power of fey is a secret. Ssssh! Nothing to see here people!