By "connect" I assume that you mean to become more solidly placed, and not to be able to resonate through it. The sound can actually resonate the carpet and flooring, or become muffled if the floor/carpet "hold" the speaker too much.
Non-Expert Idea:
Take a speaker, and feel it with your hand while playing something. The resonation and "vibration" you feel is designed into the speaker. If you prevent the speaker itself from resonating by muffling it with carpeting or whatever, it will inpact sound. Now take the same speaker, and put it on spikes, your have "isolated" to some degree the speaker from the muffling of the carpet/flooring, and it can resonate better (improves clarity, stereo imaging, and bass response), but at the same time, the spikes provide grip to hold the speaker from moving around when you crank them up.
I dunno, like I said, this is just what I have read and not personally experienced. From several "sales" sites on the internet, they talk about these points of keeping them solidly in placeas well as seperating from the floor (less sound bleed into other rooms throught the floor and getting better sound.)
I hope others can respond with first hand experience because from the marketing stuff on the internet, it sounds like they are a great tweak for speakers, and if that is true, I may end up wanting some for my M60ti's when the come in...
