as liz mclaughlin, the app is taking off with the most vulnerable, our teenagers. >> messages posts and likes, kids have a lot of ways to stay connected. one of the latest is saah rah ha. it targets adults but gaining popularity with teens. made as a way to get friends, the app allows users to send anonymous messages. >> that leaves room for a lots and lots of problems because anonymity is a license to be mean. >> but cyber bullying can occur on any social media site. 70% of kids ages 12 to 17 say they've seen it happen. >> we see this cruelty online. we have to step up and step in and say hey, this isn't right. >> sous chef says bystanders can make a difference. instead of ignoring cyber bullying, there are options for reporting abuse even reporting or blocking users. some students are count erg with a trend of cyber encouragement. >> we have to instill kindness with our own key strokes. >> to spread positive comments about their peers. >> parents also play a role >> i would tell them not to use it. >> one opinion speaking out against anonymous one. liz mclaughlin, nbc news. > >>> ♪ >>

liz mclaughlin, nbc news. >>> well, look up. a meteor shower will be visible from down here on the ground. we know find out what for. >> and the first lady is giving you a c what's new from light and fit? greek nonfat yogurt with zero artificial sweeteners. real fruit and 90 calories... you'll be wowed! try new light & fit with zero artificial sweeteners. >>> this morning there's a petition asking you to support standing up for the national anthem. it's the latest move in the ongoing debate about the nfl. football players are kneeling during the anthem to protest racial injustice. the trump make america great again committee posted this petition. president trump enough action. stand for the national anthem. end quote. >>> the wildfires that engulfed northern california have caused more than a billion dollars in damage. 42 people have died. but something caught our eye. a small mail truck still making the roundsst of the aftermooth. we tracked down the postman who is on an emotional mission. >> reporter: in devastation so vast, t