Display Ads Between Posts in Drupal
You have probably noticed that many websites tend to display advertising between posts, surrounded by relevant content.
Achieving this in Drupal is a trivial task. All you need to do is place the following code to the top of the node.tpl.php for whatever theme you are running.
If you are using custom_content and customizing it differently using a node-custom_content.tpl.php, don't forget to add the code to the node-custom_content.tpl.php as well.
<?php if ( !$page && ($id == 2 || $id == 4)) : ?>adsense code goes here<?php endif; ?>
This will add the adsense code after the 2nd and 4th post. You may want to adjust this accordingly.