WordPress.com can now tap Zemanta's magic photoifying, taggy and related linky juice
Zemanta, if you've not heard of it before, is best explained as a blogging buddy. It doesn't write your blogs for you, but it can help your posts along. As you write your posts (and update your title), Zemanta generates related links (from the Interwebs), images and suggested tags. Take a look at the screenshot above -- it shows most of the main features.
From a cynical point of view, Zemanta basically makes your blog more search engine friendly. It's an SEO tool! But, for me, just the ability to easily add images (the images are free of copyright!) is a boon of monumental proportions.
WordPress.com users can enable Zemanta from their Personal Settings (via the Dashboard). WordPress.org users (i.e. self-hosted installations), there's a Zemanta plug-in that provides the same functionality.