Meredith Darling | @merdar

What's that little pound sign in the corner of the screen with the bunched up words next to it?

That would be a hashtag. If I've already lost you, I suggest you read about it one of our previous blogs, "Evolution of the Hashtag."

How it started.

Prime time TV has been blowing up trending topics on Twitter for a while now. Marketers realized that although the topic was popular, a lot of different hashtags were being used. By providing an official hashtag, more posts would aggregate. People have moved their morning social water cooler chat to the internet, in real time.

Hashtag on TV's success is often attributed to Comedy Central's March 2011 #TrumpRoast which was retweeted over 35,000 times. You can now find them on screens during sitcoms, reality shows, award ceremonies and sports games. The idea is that there is a conversation going on right now, and you could be a part of it. And why wouldn't you? If you're like me, when I see that little opaque hashtag pop up on the screen I think for a second, then pull out my phone and tweet about it. And I'm not alone. A recent Nielsen study found that 26% of smartphone owners and 27% of tablet owners check their phone/tablet several times a day while watching TV. 45% of smartphone users and 47% of tablet users check it at least once a day while watching TV.

Incentive.

Friday nights on Late Night with Jimmy Fallon he reads his favorite tweets with the hashtag of the week. In honor of Mother's Day, last week's hashtag was #ThatsMyMom which became a worldwide trending topic in less than ten minutes. Networks are also looking outside of Twitter to gain buzz. The FOX show New Girl rewards Facebook fans with a "Fan of the Week" spotlight. If you mention them in a Facebook post during a future episode you could be featured on national TV.

Trending.

For TV shows, it's all about generating buzz. Going beyond the simple #AmericanIdol, #MadMen, #SharkWeek hashtags and seeing what fans are really paying attention to. Example: While the popular musical comedy-drama TV show Glee's most popular hashtag is - you guessed it - #Glee (used around 75,000 times during an episode), it is still able to generate trends with new hashtags. #saturdaynightGLEEver flashed on the screen for about 24 seconds during an April episode and was used over 8,500 times.

Why I love TV hashtags.

• When I look at trending topics on Twitter it encourages me to join the conversation, whether it be turning on the news or watching a sitcom.
• People who don't know what a hashtag is might not even notice it; it's discrete.
• It's easy for shows to track what is popular and what's not and to follow the conversation. I'm all about them knowing what I think so they can make the show better.
• Hashtag, number sign, pound sign, tic tac toe - whatever you call it, you have to admit it is impressive that such a little symbol can make such a big difference.

What is your opinion about TV shows displaying hashtags?