Ramadan began Saturday, and it seems like everyone has since known to insert a crescent moon icon in their tweets about the holy month of fasting -- including Hassan Rouhani, the President of Iran:
In reality, Twitter automatically adds the icon after the hashtag Ramadan--and it adds a separate icon after the hashtag Eid, the holiday that marks the end of Ramadan. It announced the new feature in a post to its blog last week. The icon only appears on Twitter web and its official apps.
The social media site has used a similar "hashflag" for the World Cup:
Twitter will also let you know when to start and end your fast if you tweet at @AlArabiya with the hashtags #iftar or #imsak and the name of your city after a hashtag.