Maybe your title won't reflect your progression, but if you list responsibilities and things learned on your resumé then that would be a clear indicator of progression.
When I first learned Rails I kinda messed around with it and wrote a quick demo app, but really wasn't that impressed with it. Coming from a C# background and ASP.NET MVC had just come out I didn't see much value in learning a new MVC framework.
However, when I started to need a language that I could use to write code that would let me easily integrate with different services and APIs I was finding that C# was cutting it for me. Not so much C# than just the .NET community. I found that the Open Source community is Ruby's greatest asset.
There are so many gems to be used in Ruby/Rails that I found that I seldom have to write anything from scratch. There is always a gem I can use to help me get a job done.
The second strongest asset of Ruby is the language itself. I found it to be a wonderful language to write in. Since learning Ruby, I haven't cared to write another line of C# again.
Is it worth learning? I say emphatically, "yes" but I would implore you to try it for yourself. Also checkout Github/Rubygems.org to see if there is a gem out there to try.