This hack is aimed at easily finding other posts from Blogosphere that are related to the one that you are currently reading. Here's how it works:
1. It picks up the post title and removes the trivial words such as "for", "of" etc.
2. It then performs a context-sensitive search operation using Google blogsearch with a combination of "all words" search and "exact phrase" search. This is to avoid irrelevent posts that could show up with a simple "all words" search as much as possible. (Note that this is still "best effort" only).
To summarize, every post page subscribes to its context-sensitive search feed and the freshest relevant posts are shown at anytime.
The best way to use this feature is to add a bookmarklet to your browser as Greg suggested while introducing this feature at Freshblog. Here's how to do it:
Find related posts
2. Whenever you are in your/another blog and you would like to read more on the topic, just click this bookmarklet and it will take you to a page that shows related posts.
You could also plug-in this feature to your blog itself by changing your template. Add the following piece of code right after the Backlinks section (indicated by </BlogItemBacklinksEnabled>) or after the comments section (indicated by </BlogItemCommentsEnabled>).
An interesting note: You can see the hack in action at the bottom of this page. The second relevant post is about aditya's similar hack to display relevant posts in "create post" page. I would have never known about it if not for this hack!! So, you never know what you are missing if you don't try this ;-)