Is yogurt which has been strained (in a muslin cloth) to remove its whey, resulting in a relatively thick consistency (between that of conventional yogurt and cheese) -- all while preserving yogurt's distinctive, taste. Labneh is a traditional food in the Levant, South Asia and Eastern Mediterranean countries. 

In western Europe and the USA, strained yogurt has seen rapidly-expanding popularity due to a much richer texture (and to a lesser extent, much higher protein content) than unstrained yogurt. Since the straining process removes some of the lactose, strained yogurt is also lower in sugar/carbohydrates than unstrained yogurt, which may appeal to those engaged in low-carbohydrate diets.

Eat it cold as a dip with crudites or crusty bread. If you prefer hot, spread it on a flat bread (sprinkle with Sumac (optional) and bake in the oven for a few minutes. Delicious!