Yes, to the best of my knowledge, FWIW is safe online when used by children. It is a non-partisan contraction that does not have offensive or inappropriate material. It allows children and teenagers to communicate politely and exchange opinion or give advice in a chat, text messages, or forums. Even parents are not to forget about reminding children to use online language responsible and not to share much personal information, yet, the abbreviation in question is not harmful, and it is rather popular in informal online communication. Know more: Fwiw Meaning In Text