WordPress SEO - Crosslinks
A lot of bloggers complain about their pages going in to Google's supplemental index. This happens to me for just about every new site I launch, but I don't worry about it because the pages recover on their own as the site ages. However, sometimes pages go supplemental and stay that way. Not a good thing.
One of the techniques for pulling pages out of the supplemental index is by improving the internal link structure between blog posts. Sure, we all have categories, tags, and sitemaps, but the best internal links are those surrounded by text rather than those off to the side in a navigation block.
And that's where the aLinks (update February 27, 2009: Looks like alinks is dead, try Cross-Linker instead) plugin comes in. I actually can't believe I missed this one since it's been available since August 2005. I'm just glad a discussion with a co-worker motivated me to do a search for this functionality. Anyway, this WordPress plugin allows you to specify a list of phrases and associate links with each phrase. As a post is displayed, the plugin will search for the phrases and turn them in to hyperlinks on the fly and transparent to users.
For old blogs this is fantastic. With some set up, you can have each of your blogs posts crosslinked in an intelligent and meaningful fashion. In addition, new posts automatically inherit the links you set up and if you ever want to change a URL, you need do so in only one spot. Awesome!
I would recommend is that you go easy on the number of links per page. Also, don't link every occurrence of a phrase on a single page. Rather, just have the first one turned in to a link. Not only is this good SEO, but you'll also keep your pages from becoming visually unappealing.
If you know of any really useful SEO-related plugins, let me know. Who knows what else I've missed.