Google has always made it easy to add a Google search box to your web site, one that offers to search only your web site or the rest of the web. That feature recently evolved into Google Custom Search Engines. With CSEs, you can configure your search box to search one or more web sites that you specify. If you have a collection of sites you like that provide information on a subject, you can create a Google CSE to search all of them at once.

Google just launched a new feature of interest to bloggers and other dynamic web sites: Google Custom Search Engines On The Fly will search your site and any site you link to, automatically. As far as I can tell, CSE-OTF's idea of related sites is pretty literal: If you search from my blog's home page, it'll only search sites linked to from the home page. Of course, what I want is a CSE-OTF that searches every site I've ever linked to in the history of the blog. Nevertheless, I get some of this effect from archive pages, especially tag searches. I"m going to try adding CSE-OTFs around this site as an experiment.