10 years ago today, a Twitter user posted a hashtag for the first time. That means a decade of a useful feature, many years of annoying advertising and several years of annoying spoken redundancy.

The idea of hashtags came more than a year after the site’s launch and was suggested by user Chris Messina who literally walked in off the street to talk to Twitter founder Biz Stone, who remembers liking the idea but dismissing Messina with an insincere “Sure, we’ll get right on that.”

Undeterred, Messina tweeted [pictured] to propose the idea of using the hash character as a way to allow people to intentionally add tweets to a collection on a particular topic. Using the hash sign was a way to avoid the collection of tweets including ones that used the same term by coincidence and weren’t intended to be part of the collection. The hash (or pound) sign worked because many Tweeters at that time were writing on phones without a full alphabet keyboard, but with a dedicated hash key.

Initially hashtags only worked with users manually searching for the term. Eventually the practice became widespread enough that Twitter management redesigned the software to automatically hyperlink any term that started with a hash sign.

The concept is now well established and harnessed for good and bad. All that remains now is to sort out those folk who speak the word “hashtag” out loud, failing to realize it’s the combination of the hash symbol and the word that forms the hashtag, not just the symbol itself.