Five Commas from Mental Floss

This video from Mental Floss is a fun and clear explanation of why particular comma usages are important for clarity.

I watched it without sound and it's clear that way, so don't feel as though you have to listen to it if you don't want to. Though I'm glad the authors note in the voice-over that you don't always need a comma after an introductory phrase. I usually omit that kind of comma, but if one is needed for meaning as in the example given in the video (!), by all means, include one.