jonkemp

Adds the “nofollow” rel attribute to category links.

Nofollow Categories

Adds the "nofollow" rel attribute to category links.

Marvie Pons

Rel Nofollow Categories is a plugin which adds nofollow attribute to categories generated by the_category and wp_list_categories throughout the blog.
Adds Nofollows to category links and an option to noindex the category pages.
Plugin by <a href="http://tutskid.com/" rel="nofollow ugc">How To | Tutorials | TutsKid</a>.
<h3>License</h3>
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with Rel Nofollow Categories. If not, see <a href="http://www.gnu.org/licenses/" rel="nofollow ugc">http://www.gnu.org/licenses/</a>.

Nofollow Categories vs Rel Nofollow Categories