Wtf is this?

Wtf is Arduino ?
It says on their site that it's a " open-source physical computing platform based on a simple microcontroller board"
What exactly does it do ? 

Essentially its a VERY basic board with modification capabilities. A micro controller technically, very useful for fun projects such as robots and led controllers. Not to be confused with a raspberry pi though. 

Edit*: it is open source, you can write in c or c++ for it, of course depending on what you want it to do.

I feel like there's this thing where you can look stuff up.  Especially things that have lots of information on them.  You could probably search for anything you want on it.  I'm trying to remember what it's called.

Oh, right!  It's the Internet.

Even more amazing is the fact that you quote their website as to what an Arduino is, then come here asking what it is and what it does.  You were already on THE Arduino website where it can answer those questions and more.  From that same website you can find numerous projects and ways to use an Arduino.  Further, they even have their own forum all about Arduino.  And yet you come and ask *here*.  Now don't get me wrong.  I like it here.  But you were at THE place for Arduino...

Yea perhaps this is more necessary , but was trying to be nice, anyways I do agree.

Sometimes I try to be nice.  Other times it just drives me crazy when people don't bother to do even cursory research on something.  A world of information is before them with so many easily utilized tools and they just ask questions expecting the answers to magically appear before them (which they probably would if they used Google).

LMGTFY is great, but it lacks that personal touch and everyone knows how satisfying it is to vent to random people online.  My post may have been a little harsh but wasn't meant to be mean.  Snark and sarcasm are hard to type without seeming as such, though.

I just hope the OP understands that he had already found one of, if not the best, resources for what Arduino is and can do.  Further, that sometimes looking for answers can quickly and easily lead to more information that simply asking a question.

I actually did search it, but nothing was able to answer my question fully. Of course I'm not stupid and don't know how to google questions, but sometimes that's not enough to have a question answered. 

In layman's terms, an arduino is an open source microcontroller which can be applied to multiple scenarios. I've used arduinos on various spectrums- from creating my own custom fm transmitter all the way to creating a fan controller and led indicator for one of my early rigs. You can write your own code for the board using their software C and C++ library. It's very customizable as you can attach a breadboard to it or even solder on various components.

Don't get put off with people talking about C and C++ the Arduino IDE (integrated development environment) is very easy to use, and a really good introduction to code......IMHO the Arduino is more designed of makers to artists that don't have experience or necessarily want to deal with programming and code, and just want to quickly and easily implement something simple like automating a mechanical device like a light, motor or sensor.