There are lots of companies that are built in Python big and small. Some examples are Dropbox, Slide, Youtube, Quora, Yelp, etc... It's definitely a scalable language and something I'd highly recommend.
As a disclaimer, I don't have any knowledge in Ruby/Rails but I'd definitely still recommend Python. You'll come across between choosing 2 and 3 if this is the path you're heading down, stick with 2 and move onto 3 later. This will make much more senes once you look into Python.