The masks are simply not effective at all if you don't address the other sanitation procedures.  

I just so happen to be living with the pro from Dover, my wife.  She teaches pre-school disabled children which pretty much insures she gets exposed to every bug that comes down the pike.  During the day, she has to be almost anal compulsive on hand washing as well as spot cleaning obvious contamination.  Hand sanitizers is one of her mainstays when water is not available.  Come in contact, wash your hands before you touch contact areas on your body.  

The hardest part is not touching your eyes or mouth except after a cleaning and paying attention when you may have contamination.  Touch a door knob, no mouth or eye contact till you wash etc.  This goes for your clothes and arms/body parts too.  

Once she gets home, first stop is the decontamination chamber, the shower and a change to fresh clothes.  Yep, your own body is a potential infectious contact area.  Rub your pants, don't rub your eyes.  Just before you eat, wash.  

You seriously have to treat this as if your skin is a decontamination suit.  This is a major change in lifestyle for many people.  

If you follow this then if you want to protect yourself from a direct facial hit, then besides the mask, you need to address your eyes with eye cover.  

If you follow that, then you can see why many people throw their hands up and say its impossible.  Since my wife started work, we figure about a 75% reduction in infection rate compared to her early years of doing this.  Taking into consideration building up immunity factors, we estimate a reduction of 50% based sanitation procedures.  When you think about it, that's not good odds but it is some odds.  

Now its not as bad as it sounds.  The school system has a clinic just to address this issue and the first sign of an infection they go at no cost.  Flu epidemics and if they have it, they issue Tamiflu to those that test positive and prescriptions for their family members as a preventative.  A season doesn't go by that we are not battling this once or twice.  The idea is keep the teachers working and since they have contact with every child to reduce infection spread.  

I take a totally different approach.  I'm simply rude and avoid contact with anyone who's showing symptoms or in immediate contact with those who are.   A party this summer my niece shows up obvious flu symptoms.  I just kept my distance and told her why.  My brother and mother both came down with the bug.  I didn't.  BTW, I don't think it was swine flu.  Just a summer cold probably, but transmittal would be the same.  

You never know though.  The only numbers the media will give you is going to be confirmed cases and how many people go to the doctor with every sniffle?   My wife but its part of her work SOP.  That's all I know who do other than hypochondriacs.  

I have some masks for mainly doing work around the house.  I don't see I will be breaking them out unless things get really bad but then I'd be staying home a lot too.  

Tj