The term Megathread is not a villainous ball of yarn set to take over the knitting world, but a way to describe an excessive number of replies to an original post. By including all recipients of your email in the Blind Carbon Copy section, also known as BCC, you can avoid megathreads as well as, quite possibly, a number of grumpy replies.
Replies to your BCC field will go directly to you, not everyone else. Plus, those who may not want their email shown to others may thank you for your discretion.
Also published on Medium.