Well this is an interesting and heated discussion...

I can see that the general populace is extremely skeptical of a FFers ability to earn such excessive quantities of miles by flying alone, but I must relate my own experiences..

I started flying with American Airlines in 1993, while still living in London, by 2001 I had a lifetime total of some 350000 miles and a current balance around the 100k mark.. Very irregular travel, usually short hops from NYC to DFW or DTW and suchlike..

Just after 11-sep-01 I began travelling extensively, made exec plat for the first time in late 2002 and passed 1m lifetime miles earlier this year..
In other words, just by doing my regular 'commuter' flights from places like JFK-SEA / LGA-DFW / JFK-BRU no more than once a week I've accumulated more than 100000 FLOWN miles per year, over 600000 earned miles in under 2 years.

My travel is nothing special and many people here exceed my meager travel schedule week after week, so I find it eminently believable that there are million-a-year flyers out there... heck I've done 150000 this year purely domestically (ISP-BOS-SEA or JFK-SEA)

Please bear in mind that some people, particularly antipodeans will accrue huge balances with relatively few flights..

Happy flying and remember miles are for SPENDING (I spent this years accrual already )