I started watching this show as an 8 year old. I didn't remember much of it before I started watching again recently, simply because nothing other than I Dream of Jeannie and Bewitched interested me.
This show is chocked full of role models and morals, along with lots of humor, and of course, from seasons 1-5(?), the beautiful Valerie Harper!
I don't know what the CSM reviewer, Emily Ashby, means that there is sex in the show. There's none at all! In fact, it's a running joke in the series that no one can get a date, yet alone have intercourse!
Like I said, the show has great role models. Mary stands up for what she believes in, and stands up when something is wrong or immoral. Rhoda teaches us that we are ALL self-conscious of ourself, and that we all have imperfect families. Lou has no valuable lessons for children, but he's not a bad guy. Ted and Georgette have lessons in parenting (So, again, nothing for the kids). Murray teaches us to be nice to everyone in our lives (Even if he isn't always nice), even our own Ted Baxters (And God knows we all have one!) Sue Ann teaches us that it's unappealing (And unappreciated by men and women alike) to be promiscuous. Phyllis teaches teens and young adults that it's unappealing and unkind to be mean and stuck up.
This show is wonderful for anyone who can keep up with a sitcom, honestly, and I think that's ages 8 and up.