In brief, the characteristics of Web 2.0 include:

The ability for visitors to make changes to Web pages: Amazon allows visitors to post product reviews. Using an online form, a visitor can add information to Amazon's pages that future visitors will be able to read.

Using Web pages to link people to other users: Social networking sites like Facebook and MySpace are popular in part because they make it easy for users to find each other and keep in touch.

Fast and efficient ways to share content: YouTube is the perfect example. A YouTube member can create a video and upload it to the site for others to watch in less than an hour.

New ways to get information: Today, Internet surfers can subscribe to a Web page's Really Simple Syndication (RSS) feeds and receive notifications of that Web page's updates as long as they maintain an Internet connection.

Expanding access to the Internet beyond the computer: Many people access the Internet through devices like cell phones or video game consoles; before long, some experts expect that consumers will access the Internet through television sets and other devices.

Think of Web 1.0 as a library. You can use it as a source of information, but you can't contribute to or change the information in any way. Web 2.0 is more like a big group of friends and acquaintances. You can still use it to receive information, but you also contribute to the conversation and make it a richer experience.