However the tit-for-tat plays out, both companies are attempting to address many of the same potential feature add-ons to web-based mapping. Google had already featured some 3-D buildings with future enhancements likely based on recent licensing deals. Microsoft had already revealed a competitor to Street View as a beta preview, both of which are enhancements to A9's earlier photo-enhanced maps. Google's recently announced My Map's competes with Microsoft's Map Collections.

The battle for mapping supremacy continues with the rush to add new features. Unfortunately for Microsoft, being first has not been a valued differentiator. In most cases, Google's implementation is cleaner and more thoughtful (compare Street View's slick in-map photo views with Microsoft's silly car-based metaphor) and/or goodwill and search supremacy has carried it to broader adoption and press coverage.

The Zillow real estate site won me over from day one by mapping house prices for every zip code and address (even if it grossly underpriced the Japanese villa of Oracle's Larry Ellison). So when the developers made a heat map of San Francisco real estate rates, I asked them to stretch that map across the whole Valley. They answered with the giant map here — stretch the window to enlarge it, or view it full-size.

Check out the peninsula — what should we call that band of red streaking across Atherton? And the deep purple pool of San Jose proves what we all knew: No one really wants to be in San Jose.

Cool data on what's hot [Zillow blog]
Update after the jump.

UPDATE: Amy Bohutinsky at Zillow says:

Fyi — Ellison's Japanese-style home is the one in Atherton. Currently listed for $16M (recently lowered from $25M). http://www.apr.com/DesktopDefault.aspx?pageid=17&pagealias=Detail&Listin gID=40135130

Zestimate is $17.9M:
http://www.zillow.com/search/Search.htm?mode=search&zpid=15593718

But... In general we are always going to be less accurate at first glance for homes on the extreme high end. Couple of reasons for that:
1) Our Zestimate algorithm looks at recent sales of comparable homes to estimate what a home may be worth today. When you get that high, we're going to have many fewer homes to compare with.
2) Most homeowners like Larry probably have done some extensive renovations or additions since the last sale that we may not know about. So he would have to use the "My Zestimator" tool to factor these in for a more accurate value.