answer:I’m not a Rails hacker by any means, but I have played with it a bit and am familiar with LAMP and Drupal. AFAIK Rails is a relatively new framework. It seems very popular with the kids, but probably lacks the great wealth of contributed models and libraries that Drupal and PHP (respectively) sport. Thus you can probably make whatever you want to do work in Rails, but you might have to do a lot of the heavy lifting yourself. Incidentally, Facebook is a PHP site with MySQL backend. Drupal has plugins that allow easy embedding of video, uploading files, etc that would probably allow building of something similar to YouTube. I don’t know what Animoto or Foursquare are. Tl;dr: Rails can do plenty, but nothing LAMP can’t do. It’s rarely a question of “what can the language do”- it’s more “how hard is it to do $TASK with $LANGUAGE in $FRAMEWORK”