What is the difference between these: it means, that means, and which means? For example:
They gave her the nickname Katie because it means "pure." I don't know if that means she is innocent or not. All I know is that she's been a good friend, which means I can trust her.
I hope it doesn't rain. If it does, it means we won't be able to go to the park today. Of course, that means we can't meet up with Heather and Peter today, which means we'll have to reschedule our meeting with them.
We encourage the use of YouTube. For companies, it means more potential customers. Just last month, one of our clients got a million hits on YouTube, which means more revenue for them because more people were visiting their website. That means all you have to do is create high quality videos, with relevant and engaging content, and essentially your marketing is done for you.
I can use them, although I just don't understand the rules behind them. I do know that "which" comes after a comma, whereas "that" usually does not. Also, I know sometimes you can use "that means" or "it means" interchangeably, but other times you can only use either "it means," "that means," or "which means," for example.
Could someone explain why we might use one and not the other in different situations? Is there a rule that explains when to use "it means," "that means," and "which means"?