Thanks for your thoughts
Hafr,thanks for getting it. I am sad that I must go this route. But you're absolutely right: I would not let my kids wander in the malls or other places without supervision. The schools have not taught them digital citizenship. Being young and impulsive, they do not yet appreciate the longterm consequences of what they type; they are easily drawn into spats with kids online. A computer monitor's lack of face-to-face response disinhibits them. Moreover, there have been some terribly toxic and near-tragic cyber-events in our community.
And yes, we talk with them. A lot. Have you ever seen a kid's face glaze over?
They know that we are using the software as a teaching tool, to help them pause and reconsider before pressing "send." In addition, we are putting a note by the computer: "Think Before You Type: Nothing Online Is Private. Anyone can copy, paste, send."
In time, as they mature, we hope to remove the software. And yes, groomers, anorexic sites, all sorts, are of concern.
The very popular and highly regarded MacGruff safety software, recommended by many parenting and computer magazines, doesn't work on Macs. That's why I was seeking your advice about products anyone has found that may be nearly as reliable.