 Since 2007, widespread usage of the symbol to introduce metadata tags on social media platforms has led to such tags being known as "hashtags", and from that, the symbol itself is sometimes called a "hashtag".The symbol is distinguished from similar symbols by its combination of level horizontal strokes and right-tilting vertical strokes.It is believed that the symbol traces its origins to the symbol , an abbreviation of the Roman term "libra pondo", which translates as "pound weight".