So what exactly is Web 2.0? More than anything else, it's a revolution in the tech world. Web 2.0 is a platform in web technology and design that facilitates web-based communities and hosted services in an effort to promote creativity, collaboration, and sharing. A misconception is assumed when people believe Web 2.0 is a new type of technology. No. The technology has been around since the start of the web. But the use of it is only gaining momentum now through "the philosophy of mutually maximizing collective intelligence and added value for each participant by formalized and dynamic information sharing and creation."[1] Aside from the usual MySpace, Facebook, YouTube, Skype and LimeWire crowd, here are the top 5 notable leaders of Web 2.0 worth mentioning.

Flickr

Did you know there's another way to get tagged, other than by running around on the playground, trying to avoid it? Yep, it's actually much easier than chasing or being chased. It's called Flickr. It is the new Web 2.0 based technology that allows users to "tag" people in their photos. Flickr, a photo-sharing site under the umbrella of Yahoo, has the best application of semantic categorization for photo-sharing on the web. The site is set up in such a way that browsing it is simple and fun. Flickr's lead in photo sharing comes with a few add-on bonus options, like enriching the community through pools, clusters and groups, preserving rights to your photos through Creative Commons, free and professional accounts, and an open API.

NetVibes

Know the art of personalization? It's all about putting your special touch on it. Know who's made it more than simple to do on your web page? NetVibes. With RSS and Ajax technologies becoming mainstream, a smarter, more personalized form of start page has taken the lead with NetVibes. NetVibes is a Paris based company that has created an accumulation tool that enables each user to create a personalized page by pulling news feeds and data from web services into modular boxes. These boxes have customizable display options and update automatically. NetVibes is configured in nine different languages. Users are able to pull in any RSS feed on the web, including Flickr photos, Alexa charts and to-do lists, and Writely documents. NetVibes even has interfaces for Gmail and Yahoo webmail services. To top it all off, no user registration is required.

Writely

The ground-shattering idea behind Web 2.0 is that the web can take over application hosting duties from the desktop. So that means, your entire Microsoft office - from documents, lists, e-mails, and contacts to productivity tools, like MS Word, PowerPoint, and Excel - live on the internet. Having your desktop available online means it's at your access 24/7 regardless of where you're at or whose computer you're on. Namely so, Writely is a web-based word processor that runs in the browser. Everything you'd expect from a word processor, you get with Writely, including spell check, formatting, and image inserting. Writing has never been easier. Yet, Writely also makes it possible to collaborate with others on different writing pieces. Colleagues can log in, collaborate, and edit a document together and then publish the final piece either online or in print. The best part is that it's free.

Odeo

Podcasting has been around for a while now. But it hasn't ever before been easier to access than now. When podcasting first entered the market, everyone wanted in on it, and all you needed to get going with it was some audio editing software, knowledge of peak limiting, compression, and EQ techniques - just to mention a few of the basics. So obviously, it was a far-fetched concept that didn't really reach the masses, until Odeo casually walked in and simplified the podcast for the commoner. With Odeo you can record and share audio using simple, browser-based tools. All you need is a browser with Flash installed, an internet connection, and a microphone. With just that, you can simply start podcasting. The Odeo site has tools for sharing and managing audio feeds, an elaborate podcast directory and a contact manager tool that facilitates sharing audio between friends. To keep the lead, Odeo even offers a viable component that allows mobile users to record a podcast from their cell phone.

del.icio.us

Ever think of filing your taste buds in a bookmark e-catalog? Neither have I. But it is possible with del.icio.us. De.icio.us saves you from drowning in a pool of bookmarks for all of your favorites - YouTube videos, MP3's, blogs, and any other page you want to earmark for a repeat visit. Del.icio.us takes a minute to become acquainted with (what is social bookmark sharing anyway, right?) but once you've gotten the hang of it, you're hooked. Del.icio.us offers easy posting from the browser bookmark bar, the capability to sneak a peek at what your friends are reading, and organization for the crazy stuff you love finding by running tag searches. All this adds up to a truly useful web app. With del.icio.us, it's hard to lose a webpage ever again, as it links the API that gives you RSS feeds, blog posting functionality, and import/export capability between sites in your web browser.

[1] Högg, R. Meckel, M., Stanoevska-Slabeva, K., Martignoni, R., 2006. Overview of business models for Web 2.0 communities. Proceedings of GeNeMe, p.23.