What is homebrew?

I have an Acekard 2i and I am soon getting a 3DS. I see all this homebrew stuff and I am just wondering what it is.Any help is appreciated.

http://en.wikipedia.org/wiki/Nintendo_DS_homebrew

Replying to #2

Thanks. So it is simply extra software?

It is software made a home.

yes its a simpe software like ds homebrew games like Still Alive : http://www.youtube.com/watch?v=dimhZ1Hw2EU
or counter strike: http://www.youtube.com/watch?v=n-_p8KhmLgs&feature=relatedand a homebrew application like ds hobro (we browser)
and DS organize