Cloud Infrastructure (Panda & other A/Vs)

Hi all! I have some queries about cloud technology applied in many antivirus programs last years. What is the infrastructure technically in these cases?
For example in the case of Panda cloud antivirus, what we have?
a. One home cloud server or more?
b. Many cloud subservers connected to the home cloud server?
c. Subservers are virtual? Not as hardware?

 

There are many servers to distribute the load out of which the load is distributed automatically, so to end user, it may just as well look like there is just one master server.

 

Well here is how Webroot SecureAnywhere Cloud works and why it is so different from others: http://www.webroot.com/us/en/partners/technology-partners/webroot-intelligence-network and here: http://www.webroot.com/us/en/partners/technology-partners/web-content-classification

TH