clikStats is retrofitable pluggin that automatically logs the number of clicks within every post.
Add sharing buttons to your blog posts for: Facebook, Digg, Twitter, Email, Reddit, StumbleUpon, etc.
Import links/blogroll in OPML format and allow them to be inserted into their proper link categories.
This is a widget for the sidebar that shows other posts in the same category as the post being viewed.
Checks Twitter usernames mentioned in the content and in the comments (eg. @tquizzle) with the Twitter service to see if that user is indeed a Twitter
Make TinyURL-like URLs (you.com/33ks8s) that redirect to pages inside / outside your blog. Can also create human-readable aliases (you.com/facebook).
A related links plugin that allows you to manually specify links, even if they're on another site. Requires PHP5.
Let your visitors bookmark, email, share and link to your pages. Get this fast, customizable dropdown button.
wp-RDFa brings the semantic Web to WordPress
Simply adds a nofollow tag to all links within a post.
Link to a users Twitter page when you include a Twitter @username in a post and tweet the user that they have been tagged.
Replaces WordPress' default, single link widget with multiple, advanced links widgets.
A limited number of brands (up to ten) can have their latest Tweets syndicated into your sidebar.
Adds a shortcode for internal links to tags, but checks if the tag exists before linking it.
All-in-one-Qype-Suite "Qypifys" your Blog! Add tooltip-links to Qype Places, geotag Post & pimp sidebar with 3 nice Qype Widgets
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