If you watched the Super Bowl from the pre-game show through the post-game show, you saw no fewer than 26 hashtags. They were in exactly half of the national ads, from #doritos to #calvinklein. It's a staggering stat, especially compared with a paltry four Facebook mentions and a goose egg for Google+. Great news for Twitter, right?

Why does every hashtag have to send people to Twitter?

Nope, says one commentator: this isn't about Twitter, it's just about hashtags. Only two of the ads called out Twitter specifically. The rest just called out a hashtag. They weren't saying "check us out on Twitter;" they were just saying, "talk about us." That same hashtag works just as well on Instagram or Google+. Why does every hashtag have to send people to Twitter?

The short answer is that Twitter's hashtags are the most popular. #Doritos on Twitter is not exactly lively, but compared to #doritos on Instagram, it's Grand Central. It makes sense, since Twitter was the first place hashtags caught on and it actively promotes them on the site. Not coincidentally, Twitter's the first place we look when we want to check in on a hashtag. But that may not always be true. Other services have already staked out specific hashtags like #nofilter on Instagram or #gif on Tumblr. Five years from now, we might look to Tumblr or Instagram or Vine for the most lively Doritos-themed conversations, or some service that hasn't even launched yet. As more services adopt the hashtag shorthand, it gets harder and harder for Twitter to keep its stranglehold on this semantic goldmine.

It's more about the signal than the wire

That's a good thing. The hashtag isn't a technology or even a platform service like the Facebook Poke. It's more of an organizing principle, a way of opting into a larger public discussion. To get metaphorical: It's more about the signal than the wire. It's a good idea and it works. Everyone should be able to use it. And to Twitter's credit, it's not trying to lock down the hashtag. It hasn't filed any patents or groused about other services ripping them off.

hashtags are cool, everyone should put hashtags in their ads, then we’ll know what to tweet #hashtag — Alec Pesola (@atpesola) February 3, 2013

In part, that's because it can't. Twitter Inc. didn't invent the hashtag, and it wasn't even the first to use them in a tweet. By all accounts, that honor falls to Chris Messina, who picked up the hashtag shorthand from IRC protocols, and started using it as a way to organize discussions on Twitter in August of 2007. It didn't even need any new tech: a simple character-string search would surface all the tweets with a certain tag. But the act of writing "#SXSW" instead of "SXSW" was enough to turn a jumble of search results into a meaningful, intentional conversation. At the time, there were plenty of skeptics, but the last five years have shown it to be a remarkably powerful trick.

The point was for hashtags to survive across platforms as a kind of visible metadata

According to Messina, the point was always for hashtags to survive across platforms. He also uses them on Flickr, in Google Docs, and in email subject lines, as a kind of visible metadata. As long as a service gives you a text box, it’s giving you a way to catalog your content. And by making your tags visible, it makes them more likely to survive the whirlwind of retweets and screencaps that often comes with internet conversation. "Hashtags are the simplest thing that could possibly work," he told The Verge. "They're easy to learn, and they're easy to use. And they're cheap."

The hashtag can go wherever it wants. Nobody owns it. It's free

And increasingly, they’re everywhere. So-called "hashtag rap" was a punchline in 2010, but it proved how useful the hashtag can be as a rhetorical device — not quite part of the conversation, but hovering above it like a file name. It’s a convention, and once you start using it anywhere, you’re ready to use it everywhere. If users want to use hashtags on Instagram, the service will learn to oblige them (even if the service is slow bringing hash-search to Instagram’s website). If they want a service that knits together the same tags across different platforms, you can bet that will pop up too. The hashtag is too easy for developers to refuse.

To its credit, Twitter Inc. seems to understand this. When Vine launched, the app came with a whole page just devoted to promoting hashtags, more than Twitter’s ever had. Are they Twitter tags or Vine tags? Increasingly, it doesn’t matter. They live in the space between platforms. And while you may not be able to drop that Instagram into your Twitter feed (or drop that Vine into your Facebook), the hashtag can go wherever it wants. Nobody owns it. It’s free.

In that way, it’s like another keyboard orphan, the @ symbol, plugged into the email protocol 40 years ago and still going strong. Along the way, the @ has outlived hundreds of email companies, not to mention a fair number of computer companies and operating systems. The hashtag seems on track to live just as long, and outlive just as many platforms. Even if Twitter collapses, there'll still be a place to say #RIP.