An iced tea spoon, also called a soda spoon, is a thin spoon with a very long handle. It is used primarily in the United States, for stirring sugar or other sweeteners into iced tea, which is traditionally served in a tall glass. This is why the spoon has a very long handle.
It is also commonly used for eating ice cream, especially floats and sundaes. As these desserts are usually served in tall glasses, regular teaspoons or dessert spoons become inconvenient choices due to their limited reach.