Drupal is being used everywhere, from small personal sites all the way up to big business enterprises, governments, and universities. As outlined in the Predictions for 2010 article, some large companies switched to Drupal in 2009, including media and entertainment giants like Virgin, Monthy Python, Lucas Arts, Michael Jackson, Eric Clapton, Robbie Williams, Infoworld, Grammys, Emmys, Radio Netherlands Worldwide, Australian Broadcast Company, BBC and CNN as well as Reuters. Other enterprises that adopted Drupal include Symantec, Nokia, Randstad, Sony Ericsson, Mattel, Rackspace, AT&T, FUJI film and even Google! 1
If large business are staking financial capital on Drupal sites, does that mean Drupal is the right choice for your site? Maybe not.
We view Drupal as somewhat of a Swiss Army Knife; they're great tools, but if all you need are scissors, you'll probably be better off fetching a pair of scissors. On the other hand if you're preparing for the many challenges that lie ahead, and you know you'll prefer the one tool, you should learn how to use it well.
A good list of considerations is available in the article Is Drupal the right tool for the job?.