In terms of popularity, WordPress is second to none. It can be safely assumed that every third website works under the control of this system. It's so popular that recently it's been used for almost everything. From blogs through forums to online stores. Drupal is much less popular, but also keenly used for all kinds of websites. So what do these two CMS platforms have in common and what makes them different? When should you choose Drupal, and when to select WordPress?