Ever since the early 90’s and the start of the end of Bulletin Board Systems ASCII Art has become neglected unlike Pixel Art that is still doing fine. Coding, Demo scene have kept the tradition and continue to use ASCII codes extensively. One of best examples is cosmblop 4k demo. More about what is ASCII and for what it is used, and it is used ALL the time, can be found on Wiki.
Now, why would anyone use ASCII art today, in 2016? Well, I use it as source code separator and organizational tool while coding. It is especially useful with Sublime Text, where right side of the screen offers an overview of the code and Large Banner like ASCII art stands out denoting individual parts of the code.
A step from using ASCII just for creating large letters we can use them to create pictures. This started almost with the dawn of computers as they had no Graphic User Interface. When something graphic had to be shown it was done using combination of special characters from the ASCII set. They are still used today and the most famous is the smiley. Smiley is the most used ASCII art. 🙂
There are allot of archives online that organize and host tutorials on how to create ASCII art. Some of them are Chris.com and Ascii Art Dictionary. ASCII Art Dictionary also hosts tutorials on how to create animated ASCII graphics. ASCII Art doesn’t has to be black and white. Wikipedia has surprisingly detailed entry about all kind of ASCII art.