What makes Python stand out for use in web development?  What are some examples of highly successful uses of Python on the web?
As many have pointed out, Django is a great reason to use Python...so in order to figure out why Python is great for web development, the best bet is to look at why it is a good language to build a framework like Django.
IMHO Python combines the cleanest, or at least one of the cleanest, metaprogramming models of any language with a very pure object orientation.  This not only makes it possible to write extremely general abstractions that are easy to use, but also allows the abstractions to combine relatively cleanly with others.  This is harder to do in languages that take a code-generation based approach to metaprogramming (e.g. Ruby).
What are the benefits of using Python for web programming?