You've heard of a Retweet, but what about a SeeTweet? Chances are you have not. It doesn't exist. Yet.
Twitter, the social media network favored by more than 140 million users around the world, allows its users to share links, tweets, pictures and more with the click of a button, the Retweet button. When Twitter users measure their performance on the site, they look for how many retweets a particular post received. The more shares, the more people have seen it.
The question is how many users have really viewed a tweet? We currently have no way of knowing. Twitter supplies the retweet metric, as well as a favorite number to show how many users liked a tweet. The metric users don't see: actual visibility, as in the number of eyeballs.
Facebook, Twitter's so-called rival social network which went public earlier this year, reveals to brand managers just how many of its fans have viewed a specific post with a metric it calls "Reach."
Facebook explains that "Reach is the number of people who have seen your post… Your post counts as having reached someone when it is loaded and shown in news feed."
So why can't Twitter do the same?
Dan Zarrella, a social media scientist at marketing software company Hubspot, says that "it's not possible [for Twitter to show the amount of impressions a tweet has received] because of the 3rd party clients." Third party clients are built by outside software developers to give users a choice as to which application they'd like to experience Twitter in.
While many use Twitter.com and the company's mobile applications, many do not. Thousands of users choose to surf Twitter in a third party application, such as Hootsuite or Tweetdeck. In order to produce a SeeTweet number, Twitter would need to make every single application report back to them with the amount of impressions, Zarrella tells CNBC.com, and that's where things get complicated.
(Read More: Twitter Attacked? Strange Photos Appear on Timelines)
Firstly, if Twitter was to recognize impressions on third party applications "it would spike the amount of API calls because it would require a two-way connection" between Twitter and the application, Zarrella explains. This would be a burden the company may be unwilling to take on.
Secondly, third party applications, like Hootsuite and Tweetdeck, are found to be useful since the services display multiple streaming columns on one screen. Tweets fly-by quicker than anyone can read. "Is that an impression?" Zarrella asks.
Thirdly, Zarrella continues, when social analytic companies program automated computers to access tweets in order to measure sentiment analysis, would this been an impression, as well?
"The idea of an impression is based on a traditional form of media… It comes from banner impressions which major brands may care about (but) it's not something that will ever be particularly useful," the social media scientist concludes.
Far more important than views are what Twitter actually charges marketers for: replies, clicks and other forms of actual engagement with a tweet.
In other words, we may never actually see the SeeTweet metric after all.
—By CNBC's Eli Langer. Follow him on Twitter at @EliLanger.