Cloud computing is mostly about scalability. You do not need to be concerned so much about low level infrastructure details such as purchasing servers, configuring and maintaining them, hiring space in data centres, linking up data centres, etc. It converts a lot of fixed costs into lower recurring costs so makes it easier for a start up with limited capital to start operating.
There are Python libraries for accessing some of the cloud computing services and you can also host Python application code on some services that allow code execution. This includes services that can run arbitrary code on virtual machines such as EC2 and more restricted computational services like Hadoop which can run Jython. Neil -- http://mail.python.org/mailman/listinfo/python-list