The PA section here.

I'm going to be visiting Philly this summer. Has the threads here always been this dead? What am I missing?

Yes, this site is not used enough in the northeast. See the upper right hand of this screen for AMP Reviews ad. That is the best review site to use for this area. Rubmaps is no where as good either.

Is the just for massage parlors?

Not entirely, some agency and independents are reviewed, if you want agency and independent ads go to TNA Board and Bestgfe.