Apple has just made history by surpassing Wal-Mart to become the United States’ No. 1 music store.

It marks the first time in history that a seller of digital downloads has beaten a big CD retailer.

According to market research firm NPD Group, Apple sold more albums in January and February than any other U.S. retailer.

The NPD Group said that Apple probably received a sales boost during the two months when people started cashing in the iTunes gift cards (a $20 sample is pictured below) that they received during the holiday season (Wal-Mart, together with other music retailers, are actually helping Apple by selling these cards in their stores).

Although the fact still remains that U.S. consumers buy more CD’s than digital downloads, the difference is rapidly decreasing. It took Apple just a little over five years to takeover the industry and jump over huge CD sellers like Wal-Mart, Best Buy and Target.

Apple launched iTunes in 2003. The online music store was a welcome development for the music industry, which was struggling against piracy — both online and off.

“It is the first instance of an electronic venue surpassing a [brick and mortar] retail venue for any kind of media delivery,” said Tom Adams, president of consulting firm Adams Media Research.

Let’s face it.

Online content is cheaper, more attractive, and most convenient to take hold off.

After downloading our favorite songs, we can easily make our own CD of only those songs thanks to CD burning. We no longer have to buy full albums just to enjoy less than half of the songs in the album.

Aside from selling full albums online, iTunes also offer thousands and thousands of individual songs for download at 99 cents each.

Plus, having an iPod makes everything a whole lot easier. Uploading to the device is even easier than downloading the songs themselves. And with the portability of the iPod, we can take a boat load of songs anywhere with us without bringing separate CD’s of difference albums.

The music industry may be leading the way (basically because songs are much smaller in size compared to other available digital media) in the advancement but other industries are also affected by the digital media shift.

Bookstores are shutting down and newspapers are laying off thousands of employees as their readers move to prefer online reading over ink and paper.

The recent shift of readers forced advertisers to ditch the newspaper pages and also move to promote themselves online.

Video game and software developers are selling more of their products as downloads rather than CD’s. With the help of web content, these companies present their products more attractively and give out more info that help sell their products.

Even TV networks are making more of their shows available online — to compete with easily available online entertainment – in an effort to keep their advertisers.

US television network CBS has already put many of its shows on the web and even sells them online through iTunes.

CBS Interactive president Quincy Smith said he believed that the network could cater to a different demographic by offering shows through iTunes.

“I think it’s a sign of things to come, if you believe in evolution,” Smith added.