How to groups blocks with blockgroup module.
Couple of examples on how to use Views header and footer areas. We also insert a non-view block with Views Block Area module.
How to grant lists of users access to nodes.
How to manage permissions for content types and single nodes.
TagCloud module provides blocks and pages to list tags.
This tutorial shows how to add Addthis social media sharing tools to your Drupal site.
Nodeblock module allows you to define content types as blocks so you can use nodes as blocks.
Mollom is content moderation service that not only uses posted content, but also the past activity and reputation of the poster to detect spam.
Some modules that extend CAPTCHA functionality: Image CAPTCHA Refresh, reCAPTCHA, Captcha Riddler and Draggable Captcha.