No matter how you communicate online it is only as safe as you make it.
Always have your parents permission and never give out personal or identifying information on a list to potentially hundreds of people.
Read the safety information and netiquette descriptions on mail lists before joining any list.
Most email lists have strict rules about sending spam to the list, virus alerts and attachments. Be sure to follow these rules. Breaking the rules can have you banned from the list.
If you are smart and use common sense joining an email list can be both fun and safe.
The next article in the series discusses how to find email lists specifically for kids.