A lot! For starters, it's boiled coffee. And Turkish coffee is richer, stronger and served with little sugar. There are many different coffees around the world that are served strong and black- French Press Coffee, Vietnamese Iced Coffee...
One of the most distinctive things about Turkish coffee is its thick foam on top. Hulking atop your cup you'll see a tall tan cloud—it looks quite spooky if you've never seen anything like it before. The foam forms when they boil both the grounds and water together in an ibrik pot (Turkish coffee maker). If you pour some sugar at this point it will cause boiling motions to attract more carbon dioxide bubbles to form into that layer on top of the brew.
Turks offer guests a dense sugarless Turkish Delight desert that accompanies their cup of dark strong brew enjoyed without cream or milk and without any sweetener at all, and they call it Kahve fincan ezmesi (coffee with spoons).
Most Turks would be hard-pressed to drink their morning brew on American terms - black.