If Twitter is useful for anything beyond a flamethrower of breaking news and URL errata, it's forcing us to be considerate about language—we have to use space wisely. Unfortunately, the hashtag is ruining talking. #NotGonnaLie
This modern use of hashtags was pioneered several years ago by one dude: Chris Messina, a Google employee. Messina thought the old pound symbol—hitherto untapped online—could be a good way to "tag" tweets, adding order to the enormous gas cloud of noise that is 99% of all Twitter action. That function works—we could search for #fukushima or #tahrirsquare this past year and yield news.
This origin doesn't matter anymore. Hashtags at their best stand in as what linguists call "paralanguage," like shoulder shrugs and intonations. That's fine. But at their most annoying, the colloquial hashtag has burst out of its use as a sorting tool and become a linguistic tumor—a tic more irritating than any banal link or lazy image meme. The hashtag is conceptually out of bounds, being used by computer conformists without rules, sense, or intelligence, a like yknowwwww that now permeates the internet outside of the tweets it was meant to corral. It pervades Facebook, texting, Foursquare—turning into a form of "ironic metadata," as linguist Ben Zimmer of The Visual Thesaurus labels it.
But why the need for metadata when regular words have been working so well? When the New York Times decided to acknowledge the hashtag this summer (!) it quoted Messina with a line that ought to be evidence enough to indict the #:
"You kind of have to be in-the-know," Mr. Messina said. "So it's one of those jokes where you're like, ‘Oh, I see what you did there, because you're on Twitter and I'm on Twitter.' "