...And you're not the first to ask that either.
She is in part because she chooses so to be, it befits her nature. Additionally, and by her somewhat obtuse logic, sneaking and lurking in dark places is easier and simpler and quieter with less on, ergo she has extended that to mean "nothing". Additionally she simply doesn't worry about what she's wearing because she never needs to, she can travel light, she need only concern herself with her own skin and not the predations of conflict or the elements on armour or other attire. As I said to start with her nature - fey as it is - is more suited to a body at one with the world around it, on her skin and under her feet - she can feel the world around her and is much more sensitized to it.
Bear in mind also that when she does (rarely) choose a frontal assault - (pun intended) - the sight of a naked, screaming Wood Elf covered in filth and warpaint and smelling like a swamp charging out of the bushes shooting flames and/or waving an axe is pretty much going to unsettle and/or distract fatally all but the most determined of creatures. In short, she also wears nothing because it puts people off; wrong footing them and making them uncomfortable. It doesn't fit with their world view - much like her.
--
(Note from her benevolent creator: It also makes keeping her safe more of a challenge, for obvious reasons...)
I love your reasoning!!! I would most definitely be distracted by that sight, and it would be a WTF moment for sure, seeing this little naked woman come running out of no where screaming like a banshie.
Even so much as a glimpse of her would make me do a double take.That is one amazing looking sword, reminds me of the one I had in RL( until my place was broken into
) You guys make me sooOOOoo jealous, I don't know whats worse, watching the bro. play on his PC or the screenies you guys post 
http://cloud.steampowered.com/ugc/578956129117284040/953C5A90A3161BE49F96D2588F257CB46024C6FC/
http://cloud.steampowered.com/ugc/578956129117287424/6983E9A22E2F9530C2367ABF257DF6F928CE4DC5/
http://cloud.steampowered.com/ugc/578956129117298381/3A1CBB189E9A2DC2FAE999C90DB1E1022F50AC55/
tonights adventure included
http://cloud.steampowered.com/ugc/578956129117290305/1FC5594D336ACFF65A1AC9FFFDBE36548D908E65/far east on the map in the mountains well beyond mzulf
http://cloud.steampowered.com/ugc/578956129117295471/BBE331E3F813D5B1F64EF7F6FBCB0E6D4A6D3567/
http://cloud.steampowered.com/ugc/578956129117293032/067FCC0A595F377BF024ED3F8CAAB355062EA0BA/
http://cloud.steampowered.com/ugc/578956129117301320/AE9EEF3A9AE42424B03A9F8975091E2A2B0E2B0A/
First time that I fell for that trap I almost ruined my pants, the wait for something to happen was bad then the fall almost made me squeal like a girl ( forgot that I could control my decent
)
it took my soooOOOOooo long to figure out that the answer was in my palm 
Great shots everyone







I heard it was possible..... 

I like it! 

Just a couple of quick random shots of Whiterun featuring a new ENB config my buddy Kyo and I will be releasing this week on Nexus. I figured everyone is so familiar with Whiterun that would be a good spot to take a couple of pics.