yes
It makes compatible with low price memory and result wider market for the motherboard itself.
The processor size or speed does not determine how much RAM your system needs. Generally speaking, the newer the system, the more RAM you can add. The amount of RAM slots on a motherboard and the motherboard's own subsystem (the BIOS) will determine how much RAM you can add to a particular motherboard.
Yes, you can have as many as your case and motherboard will support.
I have this motherboard with 1GB RAM but it is DDR. If a Motherboard supports DDR it cant support DDR2.
No.
The faster the CPU can push data around the motherboard is mesured as a frequency
The Asus motherboard 77-12dl will be more than enough for your tpical home setup.
The motherboard, or "mainboard" of a system is given away by the name. It is the main component to a PC, as everything else tends to connect to it. for a more detailed explaination, check out this link: http://en.wikipedia.org/wiki/Motherboard
Yes.
Yes you can but you will sacrifice speed and performance also your system my be more unstable. Note if your system calls for 70ns you cannot use 60ns memory.
Because the motherboard/processor is designed with that speed in mind, so overheating and various other issues can occur much more frequently at higher speeds. Also, the process of running hardware at a higher speed than is standard is called overclocking.
A server mother is like a normal motherboard except they are geared to a server processor and can hold more than one processor usually. They also support ECC memory which is memory with error correction. They support RAID. And most can are slim to be put in what is called a U1 chassis so they can go on a server rack.