I've got a question regarding VGA ext cables

[MX2]

Why do some VGA extension cables have one pin missing?
Example

 

[Peter]

Not all pins on the plug are actually used.

http://en.wikipedia.org/wiki/VGA_connector

 

[MX2]

Then why do some cables not have missing pins

 

[Peter]

Because it's not making any functional difference whether you use a fully-populated plug or not.

 

[xtknight]

Why do these pins even exist?

4 N/C Not connected
9 N/C Not connected
11 N/C Not connected

Alignment or something?

 

[Peter]

Well, the 3-row connector was the next step up from the earlier 9-pin 2-row. So with a need for two more pins (the I2C for PnP) and a connector that has five more, you end up with three unused.