It's usually a combination of services that can be selected on an as needed basis.
The host could provide things like managed firewalls, virus and spam filtering, remote backup services. Or they could offer such things as hosting the clients email for them but not the web or db hosting.
Finally, in some cases the host also does updates or patches for clients software.
It just depends on the abilities of the host and the clients willingness to job out part of the service to the host.
Atlanta, GA and Las Vegas, NV. Colocation
We are one of the "managed colocation" providers who had a booth at HostingCon. Some of the typical managed colocation services include:
1) Hardware maintenance contracts. If your hardware fails, the colo provider will replace it within a guaranteed time frame.
2) Software maintenance. Windows/Linux system administration, often with proactive updates when a security fix comes out.
3) Firewall, anti-spam, backup, monitoring, etc. services. There are hundreds of these types of services at any managed colocation provider.
The main difference between managed colocation and managed dedicated servers is that you own the box outright with a managed colocation provider; since hardware is getting so inexpensive, this can be a viable option even for small companies.
Erica Douglass, Founder, Simpli Hosting, Inc.
»»» I founded Simpli Hosting, and sold it in 2007 to Silicon Valley Web Hosting after over 6 years in the business.
Now I'm blogging at erica.biz!