Pat Hawks

dirtysuds

You can use this to show posts from other sites on your homepage and in your archives alongside your own sites posts. 
After you activate the plugin, any post with the post type “Link” will redirect to the first link in that posts content.

Offsite Post

Automatically add links on your posts to popular social bookmarking sites like Facebook, Mixx, StumbleUpon, Digg and many many others.
More info:
<ul>
<li><a href="http://blog.itechtalk.com/2008/service_link//" rel="nofollow ugc">Service_link</a>.</li>
</ul>

Service_link

Automatically add links on your posts to popular social bookmarking sites.

Offsite Post vs Service_link