I have just implemented TagCloud on my main blog page - on the right side below the Amazon advertising (or see it here). It seems I have been mostly writing about knowledge management and blogs lately.
The tool can be used with any number of RSS feeds to create a fuller cloud, such as this cloud of all people writing about KM. But I wanted just an "ego tag cloud" on my website, so there it is. The nice thing is that TagCloud appears to parse titles and text as well as the categories from the feeds, which means this is more of a "topic cloud" than a formal "tag cloud."
For those unfamiliar with the concept, Tag clouds (or topic clouds) serve as a textual way to visualize the terms and topics that are used most frequently. Larger fonts are used to indicate more frequent term usage. Formal tag clouds reference tags that have been attached to the items. Examples of tag clouds include Technorati and Flickr. Matt Mower has done this himself at his blog. There is even a cloud for Yahoo News. The nice thing with TagCloud is that I can customize the cloud to any number of common-topic feeds in which I am interested, rather than focusing on just myself or on the entire world.
These "clouds" are an abstraction from services that aggregate content from many blogs, like MySmartChannels, Topic Exchange, or even a public Bloglines subscriptions page. They can serve as an overview or starting point for further reading. An individual tag cloud, like mine, can give visitors a general idea what I've been writing about lately.