Flickr became very popular by leveraging tagging. Bweek writes about the phenomenon that tagging is. Excerpts with edits and my comments added:
On del.icio.us, people are able to tag any link they choose for easy recall later. That tagged link is stored on every subscriber's personal area on the service - and it's added to the overall service so that users interested in a specific topic can easily find new links.The notion of end users tagging content is reverberating throughout the Web, giving people a new way to think about how information is organized and found online. Tagging potentially can eat away at traditional search. Though tags wouldn't replace search as we know it, people could turn to tags more over time, displacing time they spend on established search engines. Such tagging is already being adopted by popular startups, including blog search engine Technorati and photo-sharing service Flickr.
Until now, search engines have been the standard gateway to the web to find and organize information. No matter how many pages they index or how quickly they bring back those results, most search engines can't really put things in context. Search engines make attempts by including the Web page heading that contains the result. But fundamentally, most simply lump together everything having to do with a specific word. For instance, if you look up the words "electronic publishing" on Google, the list of results throw together the lists of electronic publishers, The Journal of Electronic Publishing, and disclaimers on copyright. On del.icio.us, you get a list of links tagged with electronic publishing, but also related tags, such as blogging, journalism, and wiki, which can help you quickly navigate to specific articles.Tagging systems allow people to work together organically to create a structure around issues, blog entries, Web links, or photos. Tags also help reveal what's popular on the Internet generally or at particular sites and provide a novel way to navigate through information. For instance, check out the tags index at Technorati. The blog search engine tracks the tags that bloggers give to their posts, photos, or links. Tagging may appear unorganized, but for the moment it's working. And as it gains more converts, it's helping people rethink what search means online.
I do not necessarily see tagging as an alternative to search. Search engines have a fundamental limitation in not being able to associate results with context. Tagging may not have the algorithmic wizadry that search engines have – but can help in creating context to search results. The two may need to work in tandem to amplify the retrieve and render experience to surfers
Category :Tags, Emerging Trends.