Here’s a trick to help you remember: “Affect” is almost always a verb (e.g., Facebook affects people’s attention spans), and “effect” is almost always a noun (e.g., Facebook’s effects can also be positive). “Affect” means to influence or produce an impression — to cause hence, an effect. “Effect” is the thing produced by the affecting agent; it describes the result or outcome. There are some exceptions. “Effect” may be used as a transitive verb, which means to bring about or make happen. e.g., My new computer effected a much-needed transition from magazines to Web porn. There are similarly rare examples where “affect” can be a noun. e.g., His lack of affect made him seem like a shallow person.