The last bout of irrational exuberance gave us a lot of dark fiber and that obviously had positive effects. However, unsavory elements (porn) and respectable ones (news.yc ? :)) can coexist in peace because of the impermeable barriers of bit packets. Social dynamics are osmotic and will lead to re-invention of the new and newly cheap neighborhoods. But will these reinvented neighborhoods be slums? Changes (the more disturbing ones) observed in the article might be temporary aberration, for slums seem to need a combination of cheap housing and proximity to unskilled jobs that pay by the hour; the daily opportunity cost of the commute is quite literal.