Where are you right now? It's a simple question for humans to ask and answer, but for Web services, location is a complex and sometimes fuzzy concept. Right now, I'm in San Francisco, and I don't care who knows it. Where in San Francisco? That's not so public. I started writing this at home, with a specific address that I don't want to print here but that I'm OK with my friends knowing. Where's my house? It's in the Noe Valley neighborhood. Although, a real estate agent might be able to get away with saying I'm in Twin Peaks.
There are two interesting projects that are making headways into handling the ambiguity of location and the conditional access most people want to assign to theirs.
First, there's the Yahoo Brickhouse project, code-named Fire Eagle. It's a location information clearinghouse. The idea is that you (or your application) tells it where you are, and then it conditionally releases that information to other apps and people. It handles data at varying levels of granularity going in and out. For example, if you have a GPS-equipped cell phone feeding it data, it will get precise info about where you are. But if you're using Facebook to update your location and you just type "San Francisco," it knows a lot less. In the latter case, it will denote your location as a bounding box framed by several latitude/longitude coordinates, in this example the boundaries of the city of San Francisco.
Your location info is locked in to the Fire Eagle data store and is only released to the apps and the people who you authorize, and only at the detail level that's OK with you. For example, you can specify that photos being fed in to Flickr with Fire Eagle data (the project was based on Zone Tag for photos) get the most precise data, but that location data about you, from your cell phone, is doled out differently to different people: Your spouse can see exactly where you are, perhaps, but random Facebook friends can only tell what city you're in--or maybe only what state.
Fire Eagle will be a set of APIs designed for developers, but Brickhouse's Salim Ismail showed me how it will also have controls for users, so they can grant or deny access to their data from specific applications, and set the granularity level for various people or groups.
Google's OpenSocial API also supports location data, but the Fire Eagle really looks like a complete and robust solution for collecting and distributing geo data. I predict a lot of Web apps will use it. It should be released to public shortly, and will likely be renamed.
What's in this for Yahoo? As Ismail says, "It enables us to provide superior services." In other words, ads. Not directly, of course. But services that use the API will be able to deliver more targeted messages to their users.
Fire Eagle handles fairly unambiguous data about location. For location data that's open to interpretation, there's another company, Urban Mapping, in the business of resolving the ambiguity. Urban Mapping has a database that knows that one person's Marina District is another's Cow Hollow, and that any specific address will actually exist in multiple neighborhoods, depending on whom you ask. Since many commerce and tourism sites locate businesses by neighborhood, getting this information right is a big deal. Urban Mapping tracks the social agreements that loosely define the boundaries of neighborhoods, and supplies that data to travel and business-finder sites. The Urban Mapping team keeps up with new colloquial neighborhood names (like RAMBO in New York and SOFA in Miami) and can place business in those locations, as a Web service, to its customers. My favorite restaurant-finder site, OpenTable is, sadly, not yet a customer.
Speaking of overlapping information, Urban Mapping got its start making lenticular city maps. As you tilted the map toward or away from you, you would see different layers of info, like subways, streets, or neighborhood names. CEO Ian White is planning to bring this cool product back soon, but in the meantime he's nursing his neighborhood disambiguation service, which is already cashflow positive.