Most servers provide services for a large number of users simultaneously, much more than a single CPU could service in a reasonable amount of time. Note that there are servers with only a single processor; those are usually used for small tasks such as a small Active Directory server.
Most definitely the xenon CPU as it is a server CPU :-)
A 4p server has 4 CPU socket in one motherboard; i.e. 4 physical CPU's(not just cores or threads) on one motherboard. A 2p server has dual CPU.
Multiprocessor
Yes there are multiple controllers on all motherboards.
Yes, usually more than one.
Yes.
It is not true.
A web server can actually mean one of two different things, either the actual computer hardware, or the software that runs on the web server, receiving requests from clients and responding to them. At first glance, the specifications of a web server may be very similar to the type of computer used as a desktop machine by many people, and in fact most desktop machines could be used as a server, given the right software. Like desktop machines, a server will have a CPU, RAM, a hard drive and an Internet connection. However, when you look more closely at these specifications, the differences become apparent. The speed of the CPU is less important in a server, as servers do not have high-end graphics requirements. Nowadays, it is becoming common to see two or more CPUs, rather than one faster CPU. Memory sizes tend to be similar to those of desktop machines, depending on the purpose for which the server is intended. Most servers will have more than one hard drive, which allows for a RAID set-up to be used for data integrity, and the hard drives will also tend to be larger than those used in a typical desktop machine. Servers may also have more than one power supply. Bear in mind that all of these components will normally be built to a higher standard, as reliability is important.
Multi-core processor
If the servers were clustered, you'd lose the redundancy. Also more than one server will obviously drain the supply faster. No reason otherwise.
Try to assign static IP addresses to servers?
All players play different servers. You may play on more than one server as well.