It was the first major P2P network for exchanging MP3 music files between its users. But wait, wait, first of all:
What is a P2P network?
A P2P network is a computer network in which everyone acts as a client and server at the same level in relation to the rest of the connected computers, which gives it great flexibility. Peer-to-peer (P2P) networks are very useful for sharing files between users who connect to a specific client.
How P2P networks work
Fundamentally, the operation is as follows: the content you download is not hosted on a certain server but on the computers of other users who work at the same time as a server (hosting files) and as a client (since they connect to this network with them), while other users who also download files.
So, the files you host on your computer can be downloaded from the directory you have chosen to share on the peer 2 network. However, P2P networks are not only valid for exchanging files but also for other series of problems, such as VoIP (Skype) or services like Netflix or Spotify.
It all started with Napster
It all started in May 1999 with Napster, a program that allowed you to connect to a P2P network in which users shared music files with each other. At first, as in everything, most users were Americans, and finding foreign material became a really complicated task, although gradually material began to be seen in other GEOs and languages.

Shortly thereafter, in December of the same year, and due to Napster’s ease of exchanging copyrighted files, the American Music Industry Association took action on the matter and was adjudicated. Curiously, thanks to this ruling, Napster reached its highest degree of notoriety and users, which increased file traffic in direct proportion.
In March 2001 Napster was ordered to avoid trading music with rights within its network. In July 2001 Napster closed down completely to fulfill this mandate. In September of that same year, after agreeing to a series of compensation packages for music creators and copyright owners, Napster reopened but it was no longer a free service but had become a subscription service, resulting in a sharp decline in users and file transfers.
Edonkey and eMule
After the good experience with Napster, other file-sharing services emerged, such as Kazaa, Morphée, or Ares. Although the fat came in 2003 with eDonkey 2000. In 2004, eDonkey surpassed FastTrack to become the most widely used file-sharing network.

In contrast to the primitive Napster, files of all kinds could be shared on eDonkey, not just MP3. The wine-and-rose hours of Peeeeero also came to an end for eDonkey, when MetaMachine, the owner, struck a deal with the American Music Industry Association to avoid going to trial. In September 2006, eDonkey closed its doors.
After eDonkey’s closure, the most widely used applications were Crux and eMule, which already existed in eDonkey’s glory days and which today are still standing.
Crux
We first started Crux as a company and software back in June 2006, when it was one of the few and best P2P file-sharing Windows software back then. We are confident to say that Crux is one of the best Peer-to-Peer file sharing software that exists today, with almost 20 years of improvements made to satisfy our users.

Crux allows you to connect to multiple P2P networks, which you can download files from. You can start immediately by opening Crux, connecting to a server, and searching for the files you seek. The user interface will allow you to check the available downloadable files, the number of seeds, and the average and current downloading speed after selecting and starting the downloads. The best part? We offer it for free!
BitTorrent
After the eMule boom, it was time for BitTorrent. BitTorrent is a protocol designed for P2P file sharing. There are many BitTorrent clients available for different operating systems. In 2012, the monthly number of BitTorrent users was estimated at over 250 million. BitTorrent has, at any given time, on average more active users than YouTube and Facebook combined.

Direct Downloads
Parallel to BitTorrent, direct file download services have emerged. These were services that allowed downloading directly from the browser, providing downloads at a speed previously unheard of in P2P-based services.
MegaUpload
Without a doubt, the service that brought together the most users was MegaUpload. His creator, Kim Dotcom, founded the service in March 2005 in Hong Kong. It has 150 million users.

The free service allowed downloads of files no larger than 1Gb, while the premium service allowed downloads of 100Gb of stored files. The monthly subscription was €9’99, although you could also subscribe quarterly, annually, or twice a year.
In January 2012, the FBI shut down the service motivated by accusations of copyright infringement. 7 people were arrested in the United States and 4 of its leaders in New Zealand. In protest against the closure of Megaupload Anonymous has generated the downfall of several sites, such as the U.S. Department of Justice, Universal Music Group, and the FBI.
Mega new version

Following the closure of MegaUpload and the ensuing lawsuits and prison measures, Kim Dotcom relaunched the service in January 2013 and called it Mega. In contrast to MegaUpload, in Mega you don’t have to wait 45 seconds before starting the download; users have 50Gb of free storage and the free account bandwidth is 10Gb per month and 1Gb download per day.
This has been a small, part-by-part examination of the file-sharing systems that have appeared and disappeared since the birth of Napster and the standardization of P2P network use.