Instead of me blabbing about it, why don't I just copy & paste what the folks over at LinkWithin have to say about it? Okay! :)
Show Related Stories Under Each Post!
LinkWithin is a blog widget that appears under each post, linking to related stories from your blog archive.
Don't Let Your Past Stories Go to Waste!We retrieve and index all stories from your blog archive, not just recent stories, making them accessible to new or casual readers of your blog who would not otherwise encounter them.
Increase Pageviews, Keep Readers EngagedThe widget links to stories that are relevant and interesting to readers of a particular post, keeping them engaged with your blog, and increasing your traffic.
Elegant, Unobtrusive DesignOur widget is minimally styled and blends in with your site design.
Free and Easy to InstallThe widget is free and ad-free. It takes a minute to get the widget up and running on your blog, no signup required!
***Well, that's a pretty good descrip', isn't it? Yeah I know!
And, oh my god, all you need to give is your email address (seems reasonable, and I haven't got any spam from them yet) ,your blog link (of course, they need to know where to put their widget!), your platform (Blogger, Wordpress, Typepad or Other - again, reasonable), and your chosen width (as in, how many related post you want there to be). Oh my god, could it be simpler??? Total recommend. (Also, you may have noticed that it is, in fat, just white as opposed to showing actual related posts - that's because it's configuring as we speak. :)
Do you use LinkWithin? Does it get you more traffic? Do you have a blog? Oh em gee please can I have the link? :)