Using seltzer to help a marinade I saw the host on a cooking show claim that using seltzer in a marinade will help the flavors better penetrate meat via the carbonation. Is there any truth to this, and how would it actually work? e.g. would the bubbles carry bits of flavor material, or somehow open "pores" in the meat...?
I would strongly doubt that the bubbles themselves would have any mechanical effect on flavor.  However, seltzer or soda water has a acidic pH, usually between tomato and orange juice. This could account for any tenderizing action. The addition of salts to some seltzers might also account for apparent changes in flavor.