The current excitement over blogs is curious, since they amount to little more than personal Web pages. Although a standard history of blogging dates the phenomenon to 1997, the key attributes of the blog - a page of selected links and comments in reverse chronological order - can be found as far back as June 1993 on the NCSA What's New site, one of the most popular destinations of the nascent Web world.

In those days, such a constantly-updated page was enormously useful, since it could aspire to provide links to almost all of the new Web sites as they came online. Today, blogs necessarily offer only a partial view of the vastly greater resources now available. This, of course, is their strength: they represent a very personal filter of the otherwise overwhelming data deluge.

One of the best examples of this classic blog is also one of the earliest. Dave Winer, a software industry veteran and co-developer of one of the first blogging software tools, has been producing his blog Scripting News since April 1997. Another of his sites shows new blogs, but the number is now so great that its simple listing is no longer useful. Today there are as many blogs as there were Web pages a few years ago; this has led to the rise of a range of blog search engines.

One of the best is Technorati, which keeps tabs on nearly 2 million blogs. Useful features include NewsTalk, the news items currently being talked about in blogs (a similar service is provided by Blogdex) and a list of the top 100 blogs based on cross- references - a kind of Google for blogs. Such links - formalised as blogrolling - have become one of the defining features of current blogs, to the extent that the entire blogosphere is becoming dangerously self-referential.

In an online world where bloggers' frenzied mutual promotion seems increasingly the norm, the Wiki emerges as an oasis of dignified restraint. It was invented in 1995 by Ward Cunningham, who now works for Microsoft. But the underlying idea of the Wiki - a Web page that anyone can edit or even delete - could hardly be more antithetical to the Redmond way. In a sense, the Wiki is to the blog what open source is to proprietary software: a communal effort where group dynamics rather than a leader's fiat determine the end-result.

As well as a Wiki FAQ, and some explanation of why Wikis work, there is a page about why Wiki deletion is not a problem (and also an interesting visual representation of how vandalism is repaired). There is another Wiki page with starting points for beginners and details of the various Wiki engines available (some of which are discussed in a useful review of the Wiki world).

As a listing of the biggest Wikis shows, the best-developed example is the Wikipedia, an open content online encyclopedia that grew out of the earlier Nup edia project. At the time of writing, the Wikipedia has over 200,000 articles - including, naturally, one on the Wiki.

The seriousness and high quality of the Wikipedia entries emphasise the main strength of Wikis: a depth born of multiple authors working together to hone material. This contrasts with the blog, which shines in its ability to offer one person's quirky and brilliant insights across what may be a vast and often contrasting spectrum of subjects. (For those who want the best of blogs and Wikis, there is also the Bloki hybrid.)

Both undoubtedly have their place in the online ecosystem, but the underlying dynamics that drive a Wiki seem likely to ensure that it will prove more enduring - just as open source's ratchet of relentless improvement means that it is slowly but surely gnawing away at any remaining performance and feature advantages of proprietary code.

Glyn Moody welcomes your comments.