I've noticed that folks who come to my site by querying through a search engine often end up on my main page and the article they are searching for has already rolled off the front page. This is because the search engine robots tend to choose the index pages as more relevant than the content pages linked to by the index pages. This is especially frustrating to me since I want my blog to serve as a reference for other Agility enthusiasts - so making my articles easily retrievable from search engines is important to me. It turns out this is a pretty common problem faced by many blogs.
I found that Jason Clark had run into this problem with his Blosxom blog and resolved it by using the following meta element on his index pages: <meta name="robots" content="noindex,follow" >. His post describes how he conditionally includes these robot meta tags through his head flavour files (using the interpolate_fancy plugin and his storystate plugin) only on his index pages and not on other pages.
For my site it is even easier. I use separate head.index pages to style my index pages differently from my htm/html pages. So I just directly inserted the <meta name="robots" content="noindex,follow" > into my head.index pages.
There are a number of other robots meta tags that I might consider adding in the future. Websnob has a thorough explanation of the tags and the robots that use them.
Hopefully over the next few months these changes will cause search engines to give their users links directly to the articles in my site.