Once a WordPress powered site starts getting quite a bit of content, the default built-in search becomes fairly useless. It just isn't very smart. If you wrote a comprehensive article about He-Man, but since have written five other articles that just mentioned He-Man in passing, a search for "He-Man" will turn up your comprehensive article sixth. There have been various tweaks and plugins and whatnot to try and make this better. But why not leverage the best search engine ever written instead?
Beginning with version 2.5, WordPress automatically handles many types of canonical redirects. A good example of this may be seen by typing your blog address into your browser both with and without the
www prefix. If you are using WordPress 2.5 or better, one of these versions of your blog URL will be immediately redirected to the other. The same type of automatic redirect may be seen for several other non-canonical URL variations, and is handled via PHP deep in the WordPress core.