Web Crossing is a particularly demanding program requiring a daemon running in the background 24 hours a day. It's a program that runs in the background all the time waiting for a request and never shuts down.
All hosts claim to have some sort of regular data backup and disaster recovery protocol in place.
One host we were with started having problems with their servers, and those problems began spilling over and affecting the performance of our forum. When we found out their mail server had been down for four days before they even noticed, we started looking for a new host. With another host we made certain in advance that we could have anonymous FTP access for our forum participants to both upload and download contributions to our library. But at last he got our anonymous FTP working, and then hackers got into the server. Our sysadmin got anonymous FTP working again, and hackers got in a second time.