Alva Review-Courier -

NEW YORK (AP) — Facebook is adding a "sleep" mode to its Messenger Kids service to let parents limit when their kids can use it.

It's the latest concession that tech companies are making as critics question whether they should be targeting kids at all. Among their chief concerns: The effects on kids are not yet known, and companies might not have children's best interests at heart when tech for kids is such a lucrative market.

Rather than kill the services completely, as some critics want, Facebook, Amazon and Google are mostly tinkering at the edges. That leaves open the underlying questions...