Zemanta is a really cool plugin that comes bundled standard with Movable Type in the most recent versions available (both for MT 4.x and 5.x). While you are writing a blogpost, it automatically scans the contents for keywords and offers you various recommendations of related content, like links, images or tags. With one click you can then add these to your post. However, Zemanta's controls can take up quite a bit of screen real estate and on slower computers with a bad internet connection it can also slow you down. This can be annoying, especially if you are not using any of its functions.