What can Ruby on Rails accomplish?

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”

RoR can accomplish quite a bit. The language style and syntax of Ruby can be said to be “more modern” than C, Java, and PHP in that it focuses on the ease of reading and writing rather than rigorous logical structures. Rails adds a high level framework to the language with loads of web-related features. These technologies combined can provide a programmer with enough tools to make a functional site of any category.

Twitter, Hulu, YellowPages, Get Satisfaction, Harvest, Urban Dictionary, and Kongregate are a few of many websites built on the framework.

So in theory, yes—Ruby on Rails can do everything a web server can do. The speed of development from an idea to the release is the issue here, especially with one-person projects. I don’t have much experience with the framework myself (I’m a Django guy), but it has been proven by many to have a fast development speed in each step of the design process.

@koanhead Ruby on Rails was launched in late 2005, so it’s not so new anymore. Also, the library base has grown since then to support most needs for a project. Database extensions, image manipulation, all that stuff.

I do agree with your statement that the kids love it. It seems to have a greater “fun factor” than C or PHP when designing websites.

@Vortico I’ll take your word for it, and I’m sure it’s a wonderful language.
However, as a sysadmin who has had to install and support a few different Rails apps, I find Rails in particular to be a giant pain in the can to administer.
When it’s up to me, I use Drupal as I find it relatively easy to install, configure and maintain. It’s possible (even easy) to do things in Drupal without knowing any PHP or any programming language.

With that said, I reiterate that yes, you can do any of the things the OP proposed and many more in Rails, and there’s no reason not to learn it if you want to.
For myself I’d rather not learn it, but it’s looking like I might not have a choice in the matter :^/

Thanks guys, This has been very helpful.

@Vortico What do you mean by “library base”. Do you mean libraries of code that can be borrowed to accomplish things like image manipulation? If so, where can I find these libraries? I’ve been looking…

@koanhead Haha! You’re absolutely right about the administration. It’s an animal of its own and works differently than other popular frameworks. I don’t have much experience with Drupal, but I managed to install it on a server in a matter of minutes. IMO, it’s more of a CMS than a web framework though.

@DrewJ I guess that’s not the correct term. I was referring to the number of standard libraries and core library.

I create sites with Ruby on Rails for a living.

I’m sure you could create that site with Ruby on Rails.

I enjoy programming in Ruby, but I don’t recommend rewriting a working site just because the language is more fun/hip/popular/whatever.