The Calais initiative by Thomson Reuters is an excellent example of Semantic Web technologies being smoothly incorporated into common web activities, such as blogging. It uses Natural Language Processing to analyze text and extract named entities (e.g. persons, companies), facts (e.g. employee positions), and events (e.g. mergers, acquisitions).
I have been using Calais in this blog, through the Tagaroo plugin for WordPress. While I type a post, Tagaroo analyzes the text using the Calais web service, and suggests relevant tags and Flickr images. So far, the plugin works very well, without any glitches. Its proposals are usually quite successful and most tags of this blog have been created this way.
Calais can currently analyze texts only in English and French, but more languages are on the way. Let’s hope we see support for Greek soon!