Peer-to-peer communication really hit the big time around 2000 with a service called Napster, which at its peak had over 50 million music fans swapping music, in what was probably the biggest copyright infringement in all of recorded history (Lam and Tan, 2001; and Macedonia, 2000). The idea was fairly simple. Members registered the music they had on their hard disks in a central database maintained on the Napster server. If a member wanted a song, he checked the database to see who had it and went directly there to get it. By not actually keeping any music on its machines, Napster argued that it was not infringing anyone's copyright. The courts did not agree and shut it down.
对等通信真正引起人们关注的是在2000年的时候，当时一个称为“Napster”服务在頂峰时刻有超过5千万的音乐迷在交换音乐。这也许是有历史记载(Lam and Tan, 2001; and Macedonia, 2000)以来最大的侵权事件。这种交换音乐的思路非常简单，成员们把他们硬盘上的音乐注册到一个中心数据库，这个数据库存在Napster的服务器上。如果成员想听一首歌，他可以查找数据库看谁有这首歌，然后直接去那儿下载。由于事实上Napster的机器并没有保存音乐在，所以他们认为并没有侵犯任何人的版权。但法院不接受这种说法，最终还是关掉了Napster。

However, the next generation of peer-to-peer systems eliminates the central database by having each user maintain his own database locally, as well as providing a list of other nearby people who are members of the system. A new user can then go to any existing member to see what he has and get a list of other members to inspect for more music and more names. This lookup process can be repeated indefinitely to build up a large local database of what is out there. It is an activity that would get tedious for people but is one at which computers excel.
然而，对等交流的下一代删去了中心数据库，让每个用户在本地维护自己的数据库，并提供包含附近系统成员的列表。新的用户可以进入到任何一个现有成员的数据库，看他里面有些什么音乐，还可以获得其他成员的列表以查找到更多的音乐和名字。这个查找过程可以无限制的重复从而建立一个大型的本地输出数据库。这项活动对人来说，可能有些枯燥，但是在这方面计算机更甚一筹。

Legal applications for peer-to-peer communication also exist. For example, fans sharing public domain music or sample tracks that new bands have released for publicity purposes, families sharing photos, movies, and genealogical information, and teenagers playing multiperson on-line games. In fact, one of the most popular Internet applications of all, e-mail, is inherently peer-to-peer. This form of communication is expected to grow considerably in the future.
合法的对等通信也是存在的。例如，乐迷共享收集的公域音乐或新乐队用于推销自己的样本音乐；家庭共享照片、电影及家族信息；十几岁的青少年玩多人在线游戏。实际上，Internet最普通的应用之一——电子邮件，从本质上说也是对等的。这种交流的形式有望在将来获得更大的发展。

Electronic crime is not restricted to copyright law. Another hot area is electronic gambling. Computers have been simulating things for decades. Why not simulate slot machines, roulette wheels, blackjack dealers, and more gambling equipment? Well, because it is illegal in a lot of places. The trouble is, gambling is legal in a lot of other places (England, for example) and casino owners there have grasped the potential for Internet gambling. What happens if the gambler and the casino are in different countries, with conflicting laws? Good question.
电子犯罪并不局限于违反版权法。它的另一个热点领域是电子赌博。几十年来，计算机一直在模拟各种事物，为什么不可以模拟赌博机、轮盘赌、扑克牌及其他一些赌博的设备呢？当然，因为在很多地方赌博是非法的。但问题是，赌博在有些地方（比如，英国）是合法的，那些地方的娱乐场主已经抓住了Internet赌博的潜在优势。但如果赌博的人和娱乐场不在一个国家，而这两个国家的法律在这方面又存在冲突，应该怎么办？这是个很好的问题。