Python 2.6 (and Py3K) introduce a new way to format strings. Perviously you did this:
"%s, Here is my string, %s!" % ('Salutations', 'Dave')
Now you do this:
"{0}, Here is my string, {1}!".format('Salutations','Dave')
At first glance this looks like syntactical-sugar. But now you can do some clever things (which you could have done before, but I think are more intuitive now). You can easily repeat strings:
def tag(name, value):
return "<{0}>{1}</{0}>".format(name, value)