"It's one of the proudest things for us ever," Bono said of the headline-grabbing September promotion. "We always wanted our music to be heard, and the idea that we could have worked for years and years [on] what we think are the most personal songs that we have ever written -- and you have to become very raw to write like that -- only then for them maybe not to be heard was terrifying. So we were just thrilled that we got a chance to introduce ourselves to people who weren't fans of listening to rock music, or people that listen to Bhangra in India, or whatever, all around the world.
"Two figures arrived out of that," he continued, "100 million people checked us out and listened to two or three tracks. And 30 million people actually listened to the whole album. So we did in three weeks with Songs of Innocence what took us 30 years with The Joshua Tree."
Asked by the moderator, journalist and author David Carr, with the benefit of hindsight, if he still considered the promotion a success, especially given the global level of opprobrium that it attracted, Bono was steadfast.
iTunes Numbers Show 82 Million 'Experienced' U2's Album
"We got a lot of people who were uninterested in U2 to be mad with U2. And I would call that an improvement in the relationship," he said to loud laughter and applause from the audience.
"And we were paid," the singer continued when the cheering died down. "No one values music more than me or the members of U2. To us, music is a sacrament. It's a sacred thing. I think artists should be paid way more than they are, but the greatest way to serve your songs is to get them heard. I'm already paid too much. I'm a spoiled rotten, overpaid, over-nourished rock star. One of the reasons I haven't been vocal about music artists [getting fair payment] is that I know I'm the wrong spokesperson for this. But I have to tell you, if I were starting a band now, aged 17 or 18, I would be very excited."
Also joining the U2 singer on the Web Summit 2014 closing panel "Music and Movies in the 21st Century" was SoundCloud founder and CTO Eric Wahlforss, House of Cards producer Dana Brunetti and TPG Growth founding partner Bill McGlashan. Somewhat predictably, it was Bono who dominated the talk with his "demand" for greater transparency from record labels over revenues -- just one of the many talking points that he raised.
"The real enemy is not between digital downloads and streaming," he told the audience. "The real enemy, the real fight, is between opacity and transparency. The music business has historically involved itself in quite considerable deceit, but if we can change that bit and people can actually see how many times they are being played, where they have been played, get direct access to the information about the people that are listening to them, get paid by direct debit, then I think even those micro-payments will add up to something.
"People pick on Spotify -- Spotify give away 70 percent of their revenues to rights-holders. It's just that people don't know where the money is because the record companies aren't being transparent," Bono went on to say before calling for "more fair models of distribution."
"I think when that happens I think the music business will be a rising tide that hits all boats," he stated.
Warming to his theme, the singer also issued a warning to artists "not to underestimate our value" in the new music economy. "Musicians, historically, were troubadours. They traveled from town to town, they sang and played for their supper for the lord of the manor, and if he liked them he would let them perhaps eat from his table. I don't like that," stated the 54-year-old.
"I prefer it when musicians are their own brands, and I prefer it when we are in charge of our own destiny. I think one of the things that makes me nervous about the present moment is that we are slightly slipping back and musicians are losing that firepower that they had. We don't have to play for the lord of the manor. The lord of the manor can come and see us and pay like everybody else."
Despite occasionally striking a defensive, combative tone, Bono's overall message was one of optimism for the long-term future, as well as his continued passion for music.
"It is clear that there are some traumas as we move from physical to digital and 20th century to the 21st century, and the people who are paying the highest price in this are songwriters rather than performers. [But] I still think forming a band is so exciting. I still think there are incredible things to play with," he stated, singling out SoundCloud ("it's like a playground for artists") and streaming services for particular praise.
"Anything that gets your songs out there I think is a good. The monetary bit of this has yet to be figured out, but I think we're in the early stages of the Internet. It's like 20 years after mankind has discovered fire. It's an experimental period, so let's experiment. Let's see what works."
To that end, Bono also revealed a few more insights into the previously reported "new" formats that U2 is developing alongside Apple. Detailed plans were unsurprisingly not forthcoming, but the singer did talk elliptically about "working with the company" and discussed the potential of adding animation and interactive visual iconography to digital music to create a "new format that has more value than a simple MP3 file."
"If we get there, we get there," he said, "but they are letting us into the lab."