A lot has been made recently of cloud computing- having the computational “heavy lifting” done by servers across the internet, rather than by the machine the user is seated at. There are some tremendous advantages that can be had in the cloud, but it can be expensive and isn’t always an upgrade.
Cloud computing usually refers to services hosted by a 3rd party, rather than a locally owned server. This is really the key point to differentiate them- having someone else look after one end of the network connection means you have a dedicated team working to keep your processes safe and operating, but it also means you give up some control of your network and information.
The actual services delivered through the cloud vary widely, too- everything from daily office overhead to remote database storage, and in some cases running whole networks of office computers by remote.
These services can also be run in-house. The calculation with a move to cloud service should bear in mind machine prices, scalability, and upkeep costs- if these don’t all align, it might be better to run a server in-house.