Back in the early days of the Internet, it really wasn't even called the Internet. It had different names by different people that used it. Of course, the story goes that it was created by academics who wanted to share information, without having to send paper copies all over the place. If you were researcher, you wanted to spend your time doing experiments and not writing everything down in legible format. This was obviously a boon to research.
A short time later, the world wide web was made. This was a metaphorical name based on the idea of a spider web, where every strand is connected to a bunch of other strands through connecting nodes, which were referred to on the Internet as links. It still wasn't all that popular, and was only used by students and professors as a way to stay in communication.
When dial up speeds increased, and switched over to cable modems and other "always on" connections, people really began to see the awesome potential. As download speeds increased, people could find more and more cool stuff online. From text files, to simple pictures, to short videos, and to the current environment of streaming live video in face to face chats.
Just only a few years ago, it was optional for a business to have a web site. It was more of a presence than anything else. But today, many businesses do most, if not all, of their business online. One of the biggest known companies to take advantage of this new model is Amazon. Purely an online shop that delivered hard goods to customers, they forever changed the way to do business.
Today, most companies spend a significant part of the advertising budget on online advertising. When Google came up with the concept for ad words, and pay per click, it changed marketing forever. Direct marketing has always been a profitable business, but until Google, it had always been a slow, mail order scale model. Not any longer.
Of course, along with that came a few dangers. Spyware and adware programs were created. To sneak into your computer and watch which web sites you visit, and what kinds of documents you read, and even what kinds of things you may be typing in your email. According to the old mail order model of marketing, spyware and adware would be the equivalent of somebody breaking into your house to see what products you use, so they could send you more targeted advertising. Of course, just like you can protect your house from thieves with a strong lock, you can protect your computer from spyware and adware programs with a good anti spyware program. These will effectively get rid of any programs you already have installed, and prevent further invasions. In short, in today's Internet environment, these programs are an absolute must.