Twitter hashtag was born on August 23, 2007, invented by Chris Messina now working as an open web advocate for Google.
The first tweet with a hashtag was as follows:
According to Twitter, more than 11% tweets now contain hashtags.
Today, hashtags make tweets more meaningful and findable, traits that many users appreciate. No conference or speech is complete without a hashtag these days.
Adoption of the hashtag initially seemed to be mostly by Messina himself, who used them profusely to mark where he was tweeting from and what it was about, until around October of ’07. During the San Diego forest fires, when people tweeting about the emergency used the same hashtag at Messina’s urging and by following the example set by other citizen journalists.
Messina now thinks hashtags are overused and that there should be different types of metadata markers, for instance /via, /cc and /by. Those have been christened “slashtags” but they haven’t caught on quite as well.