Combine Realtor's MLS-based national (i.e. US) search with HousingMaps UI (because who cares for Craigslist housing listings?), including smart ideas such as a history of past sales as featured by Redfin (who is not alone in overlaying local MLS data on maps). Mix with itinerary (by foot or car) and transportation applications à la BusMonster or TrainToBoston, as well as stats on crime (ChicagoCrime example, sex offenders in Georgia and elsewhere) and education and you could do pretty good Sim City-like due diligence before a relocation in an unknown city. No doubt there will be politics and religion by county as well.

Throw in events (you got it), points of interest, dating and calendaring (e.g. concerts, restaurants, stadiums) to get a feeling of what's the entertainment and cultural scene like. And job meta-search of course, which indeed is simply all over the map today (sorry for the triple bad pun).

All these city rankings based on whether they're friendly to hipsters, businesses or families might start to make sense. In fact, someone should base a city-management game on top these real-life tools and data sources by the way.

Speaking of data, yesterday's NYT article (Marrying Maps to Data for a New Web Service) is not bad but missed an important angle. Those applications will only be so good as the underlying data, which becomes more valuable as the applications reveal its value. There are all sorts of fun business issues at stake, starting with cooperation vs. competition between players. But I keep wondering how much users will be able to put together by themselves through client integration (e.g. GreaseMonkey scripts). There's BIG money at stake (not just the listing money).

By the way, have you noticed how fast Google's mapping API unleashed really interesting applications compared to, mostly, the arcane gizmos produced on top of its web API (maybe the fact the former is less crippled helps)? Yahoo is not sitting idle, with rentals mixed with maps. Why isn't Microsoft, a company that has been doing mapping, satellite pictures, and housing listings for years, not out there leading instead of about to trail once again?

All this, always available from location-aware mobile devices. Yummy! America is about to inject itself another big dose of economic lubricant, and neither Europe nor Asia have anywhere near the same inter-state integration and society transparency to pull it off. It's exciting to see all the threads I've blogged about for five years (obviously, like many others before me) finally weaving together. Like last time, from the almost unbearable hype (do you want to fund my searchable api-enabled syndicated mapped moblogged podcasted social local visual vertical tag clouds?), real gems are going to emerge. (update: Your odio.us Gateway to Web 2.0 Riches, Supr.c.ilio.us.)

07/26/05 update: of course there's some geekery too: Cell Phone Reception and Tower Search, free WiFi finder. And you gotta love the new hybrid mode that mixes maps with satellite pictures. Finally (for now), proof that everything has its dedicated blog now: Google Maps Mania.

08/18/05 update: Amazon A9 takes it to the streets.

08/29/05 update: GMDir, an unoffical Google Maps Directory.

11/23/05 update: Super-mashup with Yahoo! APIs: event browser.

11/29/05 update: Residential Real Estate: How fast will it tip? featuring Trulia.

02/26/06 update: Yahoo Local Event Browser.

07/25/07 update: Walk Score.

01/29/10 update: Technology is Changing the Real Estate Business