Technology ever advances, keeping even those that dislike technology constantly on their toes. There are a lot of complaints about where technology is taking us and the learning curve it takes to keep up with the Joneses. But. when it comes to something as basic as the music we listen to, however, everyone keeps up; music is part of who we are and what defines us, so any advance in our music is seen as an advance in ourselves. There is nothing we won't do to hear better music.
MP3s are the newest format; it's essentially a way to compress music down a bit, allowing minimum size while keeping maximized quality. There are a number of advantages to MP3s, making them the favorite format of today's audiophiles. The obvious advantage is that they can be used by a variety of different programs; this broad support allows people to share the file, and thus enjoy the same music, as well as trade it. That broad support allows them to be played in a variety of different ways and means, meaning that anyone can play them, and virtually guaranteeing that they will play for anyone regardless of which player is used.
The size is another advantage. Besides being able to fit more songs on players, the file can be uploaded quickly, downloaded faster, and shared at the speed of light. The obvious issue is that regulating the trading of files becomes important, but it also becomes harder. After all, it now becomes easy to trade files, as all you need to do is to share a link to the files, and then anyone with that link can download the music. More importantly, it means that the music can downloaded for free; obviously record companies dislike that feature, but that makes it great for promotional purposes, or sharing music that was just acquired at a concert that night.
Of course, an interesting advantage to MP3s is that they can be easily added to any presentation. Their small size means that they can be added to other things without adding too much to the size of the thing. They have thus been added to such things as anime music videos (clips of various Japanese (and other) animation that have been set to music), where smaller is better. The general rule is that, when it comes to something that is going to be placed on the web, the smaller that something is, the more likely that it will be seen and watched; the size of MP3s makes a lot of what you see possible.
By combining these features, music becomes an agent of community, as music can be shared by people that have no other connection to each other and thus allow those connections to spread. Music is something that is universal, and is capable of breaking down barriers. When you realize that not just music can be traded this way, as home-made broadcasts and personal recordings can also be converted to MP3s, you begin to wonder what else can be shared, such as beliefs and concepts that would be otherwise alien. Thus, by trading music, you traded thoughts as well, and the world becomes all that much smaller.