why spikes under speakers???

could you guys educate me about the use or need for spikes under speakers, it seems to me that putting an air pocket under a speaker would be the last thing you want to do, isnt bas about pressure? and if you put a gap of air between speakers and floor arent you losing some of what makes bass work? I am not claiming this to be bad, I simply want to pose my questions about this concept and get educated on why this is a good idea, and when it may not be a good idea...thanks
Get me into trouble? Yes, I could cleary see how posting on an audio related forum could get me into trouble....

It's clear by your response you believe you are much more intelligent on this subject than me, so we'll leave it at that....
I started this because I am looking into VMPS ribbon tower speakers, and Brian does not suggest using spikes, these speakers have slot loaded bass, I have AR-9 Towers now wich I cant imagine putting on spikes, but the VMPS designers recomendation got me wondering..wich is why I posted this thanks all for your knowledge
I don't use "spikes", I use Audiopoints.

These actually do work.
I never confuse "spikes" with Audiopoints, since they are totally different devices, that happen to look similar to other spikes.

Tom Lyons
Starsound Technologies
S7horton..."knowledgeable" on this subject, perhaps, but that's not the same as "intelligent".