The countModules function can be used within a template to determine the number of Modules enabled in a given Module position. This is commonly used to include Modules in a certain position only if at least one Module is enabled for that position. This prevents empty regions from being defined in the template output.
For example, the following code includes Modules in the 'user1' position only if at least one Module is enabled for that position.
<?php if ($this->countModules( 'user1' )) : ?> <jdoc:include type="modules" name="user1" style="rounded" /> <?php endif; ?>