Nowaday, attaching information to real worlds stuff and gear is a trend. Projects like Aula or HP Cooltown (everything has a web page!) are a step toward this direction. Applications like tourist navigation, collaborative work or games.
Geocoding is about embedding the location of an object in the artifact itself. At the moment, geocoding an object in the physical world is possible but difficult. Indeed, one could use RFID tag and a tag reader but there is no universal protocol to sort out the artifacts or to search them. On the contrary, web pages (kind of artifacts) could be easily geocoded thanks to tag or RDF structure format (META tags, meta stands for metadata).
For instance, tags are used on geourl. This website maps documents in cyberspace to real-world locations. You add this code in the of your html document :
<meta name="geo.position" content="41.8833; 12.500" / > <meta name="DC.title" content="Jacksons blog" / >
The first line contains the Latitude and Longitude, and the second line contains the sites name. Once the site is added to GeoURLs database, you can immediately see who else has registered Web pages in (or about) your neighborhood. These coordinates are called an “ICBM Address.” (Like, Inter-Continental Ballistic Missile old hacker slang). geourl is a search engine that can help you to search website and locations with map and vizualisations. The problem is that using latitudes and longitudes is not that trivial. GPS coordinates or those indication are not human readable as well as location names.
Another more complete format (source : igargoyle) for holding geospatial data is proposed by Dublin Core (beware xml syntax):
<dcterms:description> (#PCDATA) : The description of your location.
<dcterms:projection> (#PCDATA) : The geospatial projection used.
<dcterms:north> (#PCDATA) : Distance north or south of the equator, measured on a meridian. Same as Latitude. This number is expressed in degrees.
<dcterms:east> (#PCDATA) : Longitude in degrees east of the Greenwich Meridian, with any number of decimal places. This number is expressed in degrees.
<dcterms:elevation> (#PCDATA) : The distance from sea level. This number is expressed in meters.
<dcterms:accuracy> (#PCDATA) : The geospatial accuracy of your coordinates. If you are purposely being fuzzy about your location, pick a point near your location and under accuracy, put an approximate distance to your real location. This number is expressed in meters.
<dcterms:speed> (#PCDATA) : The temporal speed, usually obtained from a GPS unit. This number is expressed in meters.
On the one hand, we have those metadata presented above. On the other hand we need software in order to search, sort, parse and transform into graphical maps those data. At the moment, those applications are yet to be developed Use a searchbot to find your keys, your skateboard or your hipster trucker hat !!!
And what about privacy in such context ?!