There’s a new buzz-word floating around in tech circles these days. It’s “Web 2.0”. “Web” is, of course, what was once called the “World Wide Web”, which is more commonly referred to today as “the Internet”. “2.0” implies a second generation of the Web, numbered like new versions of software commonly are. Chances are you’ve already seen Web 2.0 in action, and you’re going to be hearing more about it, so its time to get up to speed on what the term means, from a layman’s perspective.

First, let’s look at what its not. Web 2.0 doesn’t refer to any kind of new physical structure of the Internet. It works the same as it did back when it was Web 1.0. Web 2.0 refers to a new level of interaction between the computer user and the content available on the Internet.

Perhaps the best way to define Web 2.0 is to look at the ways it manifests itself on web pages and sites. Many people (including me) have Yahoo’s main page set as the Home Page that their web browser opens up to. For a while now, on the right side of the page, just below the Yahoo search field, is an area that can provide personalized information to a “signed-in” user. Merely moving your pointer over, say, the “Mail” button, reveals a drop-down area that lists your newest emails and a link to older mail. Move out of the drop-down area, and it closes, all without having to reload the entire web page. This is Web 2.0 at work. It’s like a mini email program embedded in the Yahoo Home Page.

Speaking of email, many ISPs (Internet Service Providers) allow users to access their email via web browsers as well as the email clients installed on their computers. Users of Apple’s .Mac service get treated to a rich Web 2.0 experience when they manage email through their browser. Not only does the web page look like Apple’s Mail client, it even lets you drag and drop email messages between folders. Drag and drop on a web page? Amazing.

The new Web Galleries available to .Mac subscribers who want to display their photos on the web via iPhoto really show off Web 2.0 technologies. When viewing thumbnail images of your gallery, you can move a slider to change the size of the thumbnails. On a web page? Amazing!