A quick summary:
The Nutter administration is asking the city's legislative body to pass its Actual Value Initiative (AVI), which would base property taxes on a city-wide reassessment that is supposed to fix years of screwy property values across the city. Many residents would wind up with a lower property tax bill, but many – including longtime residents of more affluent neighborhoods – will pay more, in some cases much more.
http://www.citypaper.net/blogs/nakedcity/Behind-the-curtains...
A funny thing about gmaps and Philly -- Philly's changing so fast that that 'dump' is probably a new renovation by now. The building I live in now still appears on Gmaps in its unrenovated state.