Different Sidebar on Category page than on Home Page
I've noticed that the side column on the page that displays the listings from a particular category is the same side column as the homepage. This is no good because my category page runs longer than the home page does so I might want more widgets here.
Here's a simple solution. Open archive-default.php and find this code.
<?php get_sidebar(); ?>
Change it to this:
<?php get_sidebar('page'); ?>
Alternatively, you could replace the word "page" with "ad", "user" or "blog". Whichever one you want to display on the category page.