Michael Rich, MD, MPH, is Children’s Hospital Boston’s media expert and director of Children’s Center on Media and Child Health. Take a look at his blog archive or follow him on Twitter @CMCH_Boston

Q: We have a 16-year-old daughter and a 14-year-old son who are at the same school. They have voluntarily given up Facebook because of the time drain it can be, and both have fairly heavy academic loads. They are interested in starting a blog together. What are the pros and cons?

–Benefits of Blogging in Roseville, CA

A: Dear Benefits,

What a great way for adolescent siblings to connect and use their creativity together! This kind of self-expression that can be incredibly powerful—even therapeutic—for teens pursuing the developmental tasks of finding themselves and connecting with their peers. But it can also be as much of a time sink as Facebook. To help them focus their efforts and make the time they spend on this project rewarding and positive, ask your teens these questions:

“What is the mission of your blog?” Do they want their blog to focus on sports, or music, or issues in their school, or what it’s like to be a teenager? Maybe they want to offer their different age, grade level, and gender perspectives on issues that interest them both. Having a vision and mission will help them focus their blog, limit the time they spend updating it, and create a unique niche in the blogosphere that will draw readers. …