Twitter’s Hashtag Turns 10 Today. Here’s How Brands Cashed In as It Evolved From Its Humble Origins
And it created a hashtag emoji to celebrate (of course)

Twitter's hashtag, which turns 10 today, has helped unite many causes on the platform.
Twitter

Today is the 10th anniversary for Twitter’s hashtag, the number, pound or hash sign associated with everything online from brand hype to hate.