I don't know if one can even say using Drupal is appropriate in any situation. The current trend in web technologies is to get a list of keywords, formulate a project around those keywords, and then wind up with some massive headaches as a result. There are a few gems made with Drupal but the majority of sites that are made with the CMS don't scale and are haphazardly put together. There is an argument that a CMS should be usable right out of the box. No agreement is more simpler than install software => use said software. There should be no third party add-ons required.
This is where Drupal fails. To do anything remotely interesting with the CMS you have to install many and not always functioning third party modules. The modules that are built are mostly open source initiatives but they are also open source failures. Some of the modules are actually complete trash and don't scale. Basically if you are going to need a site with a full featured set of options and need scalability Drupal is not your best bet as you will wind up just customizing the third party modules anyway. It takes me approximately three-four hours to implement many of these third party features using my preferred framework CakePHP and then add the features I want on top of it as well (hint build it in CakePHP or an MVC based framework).
To Drupal's success though they have pretty much made making a blog idiot proof. No other tool allows you to setup a blog with some relative ease, download hundreds of third party additions and make your shared hosting provider weep like a little girl who just dropped her ice cream on a hot summer day. Some may say I don't know what I am talking about, but I do! I was the "go to guy" on thrillist.com. That website is 100% Drupal and it doesn't use MySQL it uses PostgreSQL, so I am well versed in the scalability of Drupal, the weaknesses and strengths. In closing, don't jump on the bandwagon, especially if it is going to run off a cliff.