The Barclays Top 125 points leaders (after the Wyndham Championship) 36-hole cut to top 70 players plus ties Deutsche Bank Championship Top 100 points leaders (after The Barclays) BMW Championship Top 70 points leaders (after the Deutsche Bank Championship) The Tour Championship Top 30 points leaders (after the BMW Championship)
Once the final 125 playoff qualifiers are set, no alternates will be allowed. It is possible for any player among the final 125 (then 100, then 70) to skip a playoff event prior to the Tour Championship, but if he did he would risk his standing on the points list, and this could potentially result in him being eliminated from the playoffs.
For the Tour Championship itself, only the Top 30 Points Leaders after the BMW Championship will be eligible. If for any reason a player among the Top 30 does not compete in the Tour Championship, he will not be replaced.
[edit] Playoff rewards
The player with the most points after The Tour Championship will win the FedEx Cup itself and $10 million of a $35 million bonus fund. The runner-up gets $3 million, 3rd place $2 million, 4th place $1.5 million, 5th place $1 million, and so on down to $32,000 for 144th place. However, in 2007, the money was placed into their tax-deferred retirement accounts, not given in cash. Players under 45 are not able to access any 2007 FedEx Cup bonuses (as opposed to prize money earned in the tournaments themselves) until turning 45. They can invest their bonus in any manner they choose, and once they turn 45, can choose to defer payment until they turn 60 or play in fewer than 15 PGA Tour events in a season. Once a player chooses to take payments from his fund, he will receive monthly checks for five years.[3][4
Basically the Fedex Cup "playoff" is 4 tournaments-each of these has money prizes but more importantly Fedex points are awarded according to finish...the top 125 Fedex point earners throughout the year started last week at the Barclays...the top 100 in points continue on this week at the Deutsche Bank Championship...
next week the top 70 continue on to the BMW--points continue to accrue and finally the top 30 play in the finale at the Tour Championship for $10M bucks to the winner...
The replies you got are essentially correct...the number of "eligible" players goes down for each of the 4 tournaments...
125 100 70 30
They have changed the format this year and are "resetting" the points for the last tournament (last year they reset at the beginning of the playoffs) which should bring more players into contention for the big prize.