Technorati launched Technorati Tags, a new, decentralized method of categorizing posts that also integrates with popular online communities and Flickr.

Browse tags

The front page displays a sampling of current popular tags sorted by UTF value. A tag’s popularity is expressed through font size: the more popular tags appear larger.

Tag page

Technorati tag page for iPod screenshot

Each tag has a page aggregating photos from Flickr, weblog posts indexed by Technorati, and links. Each page contains ten photographs, twenty posts, and fifteen links. + tag of your choice (no spaces).

Join the game of tag

How can you be sure your weblog posts are included in the Technorati tag index? If you use Flickr or already, Technorati will add your public photos’ tags to its index. If you would like to configure your weblog for inclusion in the Technorati tags index you can check a few things.

Your RSS feed and Technorati tags

Your RSS feed should have a category value for each item. I added a Technorati tags domain attribute to to each category element: <category domain=””>[tagname]</category>.

If you use Movable Type your RSS feed uses the MTEntryCategory template tag, the leaf node of your primary category. If you use WordPress category is included by default in your RSS and Atom feeds.

Your Atom feed and Technorati tags

The new Atom format specification has a category construct but for version 0.3 there is no built-in support for categories. Technorati is most likely using the Dublin Core subject element for this purpose.

If you use WordPress the Dublin Core subject element is already defined. If you use Movable Type and would like to add categories to your Atom 0.3 feed you need to do a little work.

To add categories to your Atom feed through the use of the Dublin Core subject element you must first declare the namespace in the feed element and then add a dc:subject element to each entry.

  1. Change your feed element.
    <feed version="0.3" xmlns="" xmlns:dc="">
  2. In between each <entry> and </entry> you need to add <dc:subject>[tagname]</dc:subject>
Any link can be a tag

To tag your links just add rel=”tag” to any link on the main page of your weblog. Example: <a href=”” rel=”tag”>music</a> would associate a tag of “music” with Apple’s iPod page.

Kevin Marks of Technorati, the man behind the crawler, tells me the example above would tag your post with “ipod” and not “music.” Kevin says if you want to tag a link, use

Can more groups come and play?

Hopefully Technorati is open to working with other sites utilizing tags for user-defined taxonomies. Buzznet has buzzwords and 43 Things has their lifestyle tags that could be integrated into the Technorati tag ecosystem.