A decade ago, Apple launched a revolutionary new product that changed the way people purchase music, offering a new way for independent artists to market themselves and giving record companies a legitimate way to charge for their digital offerings.

The launch of the iTunes Store on April 28, 2003 changed the musical landscape forever, giving Apple a way to cash in on the highly lucrative record industry, which had been waging war with digital music piracy.

"iTunes brought together the consumer who was looking for an easy way to acquire music and they were willing to pay, and the record companies which were insisting on it but had no strategy to make that happen," says technology expert Andy Walker.

"In the end iTunes provided a way to pay that was easy and the record companies had an easy way to collect the money and distribute their products digitally."

The formula worked. Earlier this year, Apple announced it had reached its one-billionth iTunes download. And the 10-year-old service now offers much more than just music -- branching out to books, movies, TV shows and applications.

Here are eight ways iTunes has changed the music and entertainment industry:

It convinced people it's OK to pay for music online:

Before iTunes came along, a generation of Web-savvy youngsters became accustomed to a world where music was free. Through Napster and similar services, they could share their digitized music libraries with other users and download the songs that they wanted. It wasn't unusual for a user to have a music library consisting of tens of thousands of songs -- all pirated.

Somehow, iTunes changed that and made it cool to buy music again.

"I think people have always been OK with paying for it. Their issue was if you don't want to provide me with a way to pay, to heck with you I'm going to take it anyway," Walker says.

Replaced the record store:

Remember HMV? Sam the Record Man? You'd be hard-pressed to find one nowadays, and that's largely due to iTunes. While stores that sell actual vinyl records still exist, CD retailers are virtually extinct. The weekly or monthly tradition of going to the music store, checking out the latest releases at the listening station or even getting excited about something new and obscure being played over the store's speakers has largely become a thing of the past.

"iTunes replaced the record store," Walker says.

iTunes became 'Switzerland' for warring factions:

Before iTunes came along, musicians, record companies and fans often found themselves on opposite sides of a battle no one could win. Fans wanted their music delivered digitally, musicians wanted to get their tunes out to as many people as possible, but record companies refused to give it away for free -- and even tried to prosecute those who downloaded it illegally. Without a proper medium to get the music out to fans, no one was happy.

iTunes offered a neutral compromise that worked for everyone.

"Really, iTunes became Switzerland," Walker says. "It brought together the consumer who was looking for an easy way to acquire music and they were willing to pay, and the record companies which were insisting that [consumers] pay but had no strategy to make that happen. In the end iTunes provided a way to pay that was easy and the record companies had an easy way to collect the money and distribute digitally."

Made Apple (even more of) a superpower:

While Sony and others have their own token digital download services, nothing even comes close to iTunes.

Steve Jobs, Apple's former CEO, brokered deals with all the major record labels that ensured they had a user-friendly way to sell and deliver their product, and received a fair share of the profit --- with Apple of course getting a cut for serving as the broker.

"No one else had been able to do that because the people who'd been building the digital record stores were record companies themselves so they weren't going to do deals with each other," Walker says.

Created a platform for independent artists to self-promote:

In the past, independent musicians had little or no access to the marketing machinery that could make their albums accessible to millions of people. A website, MySpace page, merchandise tables at concerts, guerrilla marketing tactics and maybe a stack of CDs at the local music store were about the extent of the options available.

But iTunes allowed anyone and everyone to sell their music on the site. A successful independent artist could theoretically bypass the record companies and market directly to their fans -- a potentially lucrative arrangement.

"It's created a level playing field. You don't need a record label anymore, you can be your own little record label," Walker says.

Allowed consumers to weed out the 'filler':

On iTunes, there's often no requirement to purchase an entire album. Consumers can purchase their music song by song. As a result, the 'filler' tunes that are often included on an album to fill out the track listing, may simply not sell through iTunes.

"When somebody makes a B-side they have to think twice about what they're going to put on the B-side because it's not going to sell on iTunes if it's not halfway decent," Walker said. "In the end we get to choose. We're not forced to spend $16 on 16 songs -- we actually only have to pay $3 for the three songs we want."

Made video rental stores redundant:

In addition to the disappearance of music stores, video rental shops have also become few and far between in recent years, partly thanks to iTunes.

Along with on-demand and pay-per-view movie services and Netflix, iTunes also now offers rentals sent directly to your screen -- whether it's the latest episode of Game of Thrones or a classic movie.

"Once upon a time I'd trudge down to the movie rental store, grab a bunch of discs and have to return them the next day and deal with late fees and that sort of thing. I don't anymore, I just turn my computer on and if I have a fast Internet connection I can be watching a movie in minutes."

Expanded to books and more:

Walker predicts that iTunes will be rebranded and re-envisioned in the near future to accommodate its recent growth. Even the name feels a little dated, since the site has grown to offer movies and TV shows, apps for mobile devices, even e-books.

And because the site has been expanded and stretched to serve so many purposes beyond its original intention, it may be time to rebuild from the bottom up.

"If you spend any time with iTunes you get the sense it was a rowboat that became a ship. They nailed on pieces to it and it does work but it feels a little clunky at times," Walker said.