The plant example is a little flawed because it is clear that one event follows the other. No one would ever say that the plant's death caused it to be deprived of sunlight and water.
"Correlation is not causation" isn't nonsense if you're talking about two events that don't have a clear hierarchy. Suppose that rather than porn causing blu-ray's success, porn went with blu-ray because it was more successful. I'm not knowledgeable about the porn/blu-ray relationship so one of these possibilities may be provably false. I just didn't want to have to come up with a car analogy, and the porn analogy was right there.