Remember the “Semantic Web” (Wikipedia if not)? It sprang out of Tim Berners-Lee’s vision of a web that was smarter about sifting, analysing and relating the explosion of information fostered by the Internet. It sounds full of almost mystical promise (as Berners-Lee puts it):

I think maybe when you’ve got an overlay of scalable vector graphics – everything rippling and folding and looking misty – on Web 2.0 and access to a semantic Web integrated across a huge space of data, you’ll have access to an unbelievable data resource.

While we are waiting for this to arrive in all its fullness, Scott Ziegler is working on a nifty little plug-in for Mail.app that analyses the headers and body of emails in order to list emails related to any selected message.

It lists them in a pane on the side of Mail.app’s interface:

Messages are listed by relevance. Clicking on the subject line of each one opens the email in a new window. In the screenshot above you can see RelatedMail listing other emails I have received on the topic of the email highlighted in the Message List — converting paragraphs into bullet lists in Mail.app. It does a pretty good job.

Related mail does this by creating a database all of its own inside your Mail folder (which takes a bit of time and uses up a bit of disk space):

The pane can be opened and closed by selecting its “Show/Hide Related Messages” option in Mail’s View menu.

Scott says upfront that the plugin is still in development and lists a series of known issues with the current build on his web site which also contains handy instructions on installing and removing the plugin and explains the colour-coding and formatting used in the pane to indicate various categories of relatedness.

It’s fun to play around with. It’s useful too. And it’s freeware (at the moment). Get it from Scott’s web site and get a small glimpse into the future of the Semantic Web.