What is that song? It's a simple question but one Shazam has built an audio-recognition empire on, having answered it billions of times through its app.
It was first answered on 19 April 2002. T Rex's Jeepster was the very first tag, when the service was then called 2580. Skip to 2013 and the 10 billionth answer was given this month as Lady Gaga's Applause.
"It took 10 years for the first billion, 10 months for second and two months for the last billion," explained Shazam's Chief Product Officer Daniel Danker to TechRadar, who puts Shazam's immense popularity down to smartphone growth and the service "being an inherent behaviour now".
"The other day I was in a restaurant and it played great music. They were playing a few recognisable songs but when there was one that wasn't I could see three people 'Shazaming' it," said Danker.
"When it is that embedded in people's lives then it is easy. Shazam is fun and simple and it just works."
According to Danker, 500,000 songs a day sold are sold through Shazam, which equates to around 10% of digital music in the world sold.
"When you hit these numbers, artists think of you in a very special way," he said.
"There is intent with Shazam. If you are in the search business and someone is looking for a vacation in Barbados that is intent and we have a similar thing and that is hugely important."
Keeping it simple
'Simplicity' and 'intent' are the key features needed, believes Danker, for Shazam to expand beyond the music space and into the TV one.
Shazam's chief product officer has only been at the company for four months, but his move from the BBC where he was key to the success of the iPlayer and Red Button technology, is telling of where Shazam is going.
According to Danker, it wants to take the success of what it has done in music and apply this to the TV industry.
"When you are reaching more than 70 million users a month you have got an incredible platform. What we are doing now is shifting that energy to television," he explained, before correcting himself by saying: "Actually shifting is the wrong word to use, as we are scaling up what we are doing on music, then using our technology to build a business in television."
This was seen last September with the announcement that Shazam's technology would now work with all US TV, offering up relevant show information through the service. Although Shazam for TV has yet to reach other shores, Danker believes a lot has been learned from the experience.
"We started with a ubiquity bed, where you could Shazam any show on 160 channels. This was so we could start learning what people are doing when you have that canvas. That, for us, was a great platform for data," noted Danker.
"What we learned was that 85% of Shazam's users, Shazamed television. That's not because they are Shazaming soap operas but they are unsurprisingly starting with Shazaming music on these shows. So, we have started adding calls to actions on programmes and to adverts. You are going to see a lot more of this too."
Shazam has cropped up on some adverts globally. It was used recently on the commercial for the Jaguar F Type, but it will be a bit of a wait for TV show recognition to appear in other countries.
The reason Danker gives for this is an honest one: "You will see more Shazam-based TV stuff but we haven't nailed it in the US yet. Nobody has nailed it in the US yet.
"The US is a fantastic market to start in television, though. But I want to see us in a bigger and bigger role in the conversation of how television is commissioned, created and distributed."
According to Danker, Shazam is forging itself into the ultimate second screen experience for TV, even though he admits he hates the phrase.
"I am not happy with calling it 'second screen' - we have to remain human here," said Danker.
"Try to picture any of these sentences being muttered by someone not in the industry: 'what we need now is that second screen' or 'what we need is that social TV app'. No!
"What people do say is: 'I really want to share this with my friend' or 'I really want to know who this actor is'.
"The beauty of Shazam is that it has become a verb. I don't use the words companion app, social app, second screen app, what people want is to Shazam it, so they can get more out of it. We don't need to label it. Let's follow what the users are saying."
And the users are talking - they are asking a lot of pretty simple questions.
"Who is the actor? What else have they been in? How do I get that product? These are all super common," said Danker who explained that this also stretched to TV advertising.
"This whole notion that TV advertising is something you need to suffer through to get TV isn't how we view it at Shazam. Just like people only Shazaming the music they are interested in, no one in their lives have ever Shazamed an ad that they didn't want.
"The only people Shazaming ads are those who want to know more. This is a natural scenario where Shazam can add value. We don't want to pepper your life with things you are not interested in, but we do want to offer stuff you are interested in."
Shazam is certainly not the first company to try its hand at offering apps for television. In fact another BBC veteran, Anthony Rose, heads up Zeebox a real-time social TV rival to Shazam. But Danker believes that TV apps that rely on real-time television are flawed from the outset.
"If you Shazam a show or an ad when it is live or when it aired a week ago, you get the same quality of experience," said Danker.
"We don't depend on it all being live. That's important as we don't want to force users using our product when they are watching live TV only. That is an inherent problem with social apps. What is the conversation right now? If I am five-minutes time delayed then this shifts from being a potential value add to a spoiler.
"On average people will pause a programme six times every hour and yet you think you are watching it live. You are not. Think about a Super Bowl party where you saw a great play, did an instant replay and skipped back. Now you are 30, 40, 50 seconds off of live and you have an app on your phone that shows you what happens live - that's awful.
"We get to synchronise with the very moment."
TV's transitions phase
With Shazam betting so much on TV watchers using an app while watching television, you would think that the market for second screen television apps was a rosy one, but even Danker admits it is not.
"Television channels see creating apps as a liability as it is not helping their bottom line. So we are in a transition phase, we are still in a place with TV programmers where they are not sure whether they should be doing these apps themselves."
Danker gives the example of ABC which recently announced that it was no longer supporting its second screen app but agrees it is the best thing ABC could do as it "is too expensive and it is not delivering the results".
"But what if they took the content they already have, give it to Shazam we can take away the cost and complexity," he said. "We can give them more users and it makes sense for them."
So, what does the future hold for Shazam? A simpler experience, according to Danker. Given that Shazam is an app with one big button you would think that it would be difficult to make is simpler but Danker will try.
"When your goal is to be effortless and simple to the user, then the more things you can peel away the better," Danker explained.
"While I celebrate the fact that we are one button I always ask: do we need to be a button, can we remove the button?
"Our mission is to help people recognise and engage with the world around them. We are not just focused on music and television, but that is where we are starting."