Did you notice the emoji explosion on social media this week? Tuesday was World Emoji Day, and a lot of brands and celebrities weighed in. Dolly Parton shared this emoji-inspired tweetusing the butterfly and music notes emoji. Ellen DeGeneres shared a recipe for a pride heart emoji-shaped cookie. And Apple released a preview of 70 new offerings — including a peacock. But there was a serious side as well. Groups that tackle global issues, from health to poverty, joined in. Yes, the U.N. and the World Bank used emojis to talk about their concerns.Is that a little ... silly? Or just a different way to send out their message?An emoji can be "a fun and playful" way to address global issues and transcend language barriers, explains Hope Randall, a communications officer at Defeat DD, an initiative to raise awareness about diarrheal disease in low-income countries. The group often uses the "poo" emoji in its social media.In 2017, the Bill & Melinda Gates Foundation lobbied for a mosquito emoji to raise awareness about malaria. (The foundation is a funder of NPR and this blog.) The skeeter was turned into an emoji in February. Another group, Plan International, is pushing for a menstruation emoji (in the shape of a blood drop) to help break taboos around periods.For this year's #WorldEmojiDay, groups in the global development sector stuck them in quiz questions, created rebuses and shaped them into words (see the World Food Programme's offering below). Here's a sampling.UNICEF looked for emoji that resemble faces from its archival photos. Amnesty ran a name-that-tune contest. Check the tweet replies for hints. Copyright 2018 NPR. To see more, visit http://www.npr.org/.