Filters and behaviors can be added using the plugin.

Installation:

Unpack and upload it to the /wp-content/plugins/ directory.
Activate the plugin through the 'Plugins' menu in WordPress.

Here are some key features of "Hunk External Links":

· Process all outgoing links, rather than only those within your entries' content.
· Add an external link icon to outgoing links. You can use a class="noicon" attribute on links to override this.
· Open outgoing links in new windows. Note that this can damage your visitor's trust towards your site in that they can think your site used a pop-under.
· Add rel=nofollow to the links. This is not very nice for those you're linking to, but useful to avoid PR leak.
· Open outgoing links in your own page, Then you can go back.

Requirements:

· WordPress 3.0 or higher