Regarding the low dose of Xanax being effective, active, therapeutic or whatever you guys are arguing about...I'm not taking sides at all here but if someone needed Xanax for a medical reason, (anxiety, panic attacks, muscle relaxation, sleep...whatever) they would most likely need at least 0.25 mgs.
That said, I have taken benzos off and on for years. If I haven't taken any for awhile, I can take 0.15 mgs (150 mcg's) of Xanax and feel it relieve my anxiety. I also take that small amount to help with sleep sometimes. My girlfriend can take half of a 0.25 mg tablet (0.125 mgs) and it knocks her out cold.
Point is, everyone is different.