HAHAHA, that's awesome! they initially only announced sunday and monday night shows, which sold out within seconds (i managed to get a pair of orchestra seats for the sunday show, tried several times again on another computer and only got "no seats available"). i'm certain that scalpers bought up a lot of tickets for these two shows. then they announced the friday show... and i'm willing to bet that once it sells out, they'll announce a saturday show. they're doing the same thing in boston.
so, if you want to see the pumpkins in philly or boston: keep checking TM until the fourth show is announced, or wait until shows get closer - people will be dumping tickets. there is obviously enough demand for two nights in these cities, but i'm thinking that four nights is close to too much... there won't be anyone left who's willing to pay big prices.
nice one, although it might suck a little for folks who bought crappy balcony tickets instead of waiting for the other shows to go on sale.