I think a better thread would be to explain in layman's terms what all of these technical phrases mean, then to demonstrate them with simple diagrams and calculations. This would allow each member to work it out and then post on the thread to ensure they are correct.
For example La Bam, your question:
The cabinet provides the load not the amplifier. So, you amplifier has a minimum load (in ohms) that it is happy with. I am going to assume that as above, in bridge mode you can have any impedance as long as it is higher than 4 ohms. Since your cabinet is 6 Ohms, your amplifier sees that load and thus that would be the "measured ohmage" across the output terminals. This is of course Impedance which is an AC measurement, not to be confused with Resistance which is a DC measurement that you'd make with a simple 'multimeter'.
What the 6 ohms measurement does do (on paper at least) is affect the power reading of the amplifiers output. At 2 ohms difference though in this scenario, it's not worth bothering about as your 6x10 cones are moving plenty of air anyway.