Here's some of the common social networks and their associated share link formats. They are all similar, but of course there's no standard . . . that would be too easy.

These are subject to change at any time. Please let me know if I've missed something.

<!-- twitter -->
<a href="http://twitter.com/home?status={{ title }}
{{ request.build_absolute_uri }}" title="Click to share this post on Twitter">twitter</a>
<!-- twitter -->

<!-- facebook -->
<a href="http://www.facebook.com/share.php?u={{ request.build_absolute_uri }}&t=<title of content>">facebook</a>
<!-- facebook -->

<!-- reddit -->
<a href="http://www.reddit.com/submit?url={{ request.build_absolute_uri }}&title={{ title }}">reddit</a>
<!-- reddit -->

<!-- digg -->
<a href="http://digg.com/submit?url={{ request.build_absolute_uri }}&title={{ title }}&bodytext={{ description }}">digg</a>
<!-- digg -->

<!-- delicious -->
<a href="http://delicious.com/save?url={{ request.build_absolute_uri }}&title={{ title }}">delicious</a>
<!-- delicious -->

<!-- myspace -->
<a href="http://www.myspace.com/index.cfm?fuseaction=postto&u={{ request.build_absolute_uri }}&t={{ title }}
&c={{ contetent }}">myspace</a>
<!-- myspace -->

<!-- stumbleupon -->
<a href="http://www.stumbleupon.com/submit?url={{ request.build_absolute_uri }}">stumbleupon</a>
<!-- stumbleupon -->

<!-- linkedin -->
<a href="http://www.linkedin.com/shareArticle?mini=true&url={{ request.build_absolute_uri }}&title={{ title }}
&summary={{ description }}&source={{ source }}">linkedin</a>
<!-- linkedin -->

<!-- google bookmarks -->
<a href="http://www.google.com/bookmarks/mark?op=add&bkmk={{ request.build_absolute_uri }}&title={{ title }}">google bookmarks</a>
<!-- google bookmarks -->