At the time, I thought this tag was making reference to Wimsatt's "Bomb the Suburbs" book, and that maybe "urburbs" was a misspelling or abbreviation of "Suburbs". But I underestimated the sociological sophistication of the taggers. "Urburbs", it turns out, are
older neighborhoods within the typical American town or city. In most instances, these neighborhoods are the earliest suburbs; the tracts that were developed to house the more affluent families of America's white middle-class society shortly after World War II. The urburbs lie in rings around the outside of the central core of the "downtowns" and are not to be confused with historic urban housing, where the new suburban residents of the late 40's and 50's once lived, or with apartments for singles and newly married, or houses originally developed for the gentry.
(Quoted from "Redeveloping the Urburbs: Salvaging the Origins of Sprawl").
That definitely makes Hyde Park an urburb (though it predates WWII).