Drupal 8 has been in the works for some time now, and looks pretty exciting. We’re particularly excited about web services becoming part of Drupal core, rather than being something you can add on. We have built custom web services applications for Joomla & SouthWare e-commerce sites, but would love to be able to do that more easily in Drupal too.
Check out the Drupal 8 initiatives currently underway. Drupal 8 is still under pretty heavy (but steady) development and may be released some time during 2012. You can read up on the various Drupal versions here.
Drupal 6 is the most widely used version and is very stable at this point, with many modules available. Drupal 7 has been out since January 5th 2011 and took three years to develop. There are still many modules that do not yet work in Drupal 7, but that is a given considering how young it is. As a casual user the main difference you’ll notice between Drupal 7 and 6 is Drupal 7’s very attractive interface, which is reminiscent of WordPress. That is mainly due to its use of lightbox / modal effects and well-designed UI. User interface was definitely an area in which Drupal 6 was lacking, and as a result it became a main focus for Drupal 7. With that under control, we’re very pleased to see Drupal 8 focused on more business-oriented features such as web services.