The hashtag has become synonymous with Twitter, but that's not how things have always been. It was actually created by a user, not Twitter, and about a year and a half after Twitter was started. Back in March 2007, Chris Messina was getting frustrated with the volume of uninteresting content showing up on his Twitter feed. Over the next few months, he and others devised a way to make the new social media platform more engaging.

Some of his original ideas consisted of turning Twitter into a forum. He realized that idea would be too complex so in the end, he decided to create a signal that would sort tweets by a user's interests. He tweeted out the idea to his followers and thus the hashtag was born.

Mr. Messina, a product designer and startup enthusiast, was never a Twitter employee. Since that day 10 years ago, Messina has been employed at Uber and Google and is still an avid tweeter. He views the hashtag, a single character to classify the content of a message, as the simplest idea that could work. It is now become a tool that allows people to more easily participate and classify social media conversations on topics that they enjoy. It's also become commonly used on other networks like Facebook and Instagram, and even into spoken conversation.

There are now about 125 million hashtags circulating Twitter every single day. They can be used to find content about a certain event, show support for a cause, tag the content of your message, and more. In just 10 years, something originally called a "tag channel" and demarcated by the hash character, has become part of our global language and modern tech culture.