"I.e." is short for "id est," which is Latin for "that is" or "in other words". It is used to clarify or elaborate on the subject that comes before it. For example, "I love citrus fruits, i.e., oranges, lemons, and limes" means that the speaker loves oranges, lemons, and limes specifically.

In contrast, "e.g." is short for "exempli gratia," which is Latin for "for example". It is used to introduce examples and illustrate a statement. For example, "I love citrus fruits, e.g., oranges, lemons, and limes" means that the speaker loves citrus fruits in general and is providing examples of the types of citrus fruits they like.

Remember that "i.e." and "e.g." are not interchangeable, and each has its own meaning and usage.