Ever need to know the altitude at a given location on the Earth?
Well, there are several free resources to the rescue:
Geonames offers two services using the SRTM data, and also the GTOPO30 from the USGS. Geonames gets bonus points for also returning the results in JSON. Geonames also uses a larger dataset - lands within 60 degrees north and 56 degrees south.
As "points" become rather ubiquitous among neogeographers/web-mappers, they're moving into more complex geometries and especially 3D space. Having access to data means it is very easy to tie into services and applications. For example, making a hiking profile given just 2-d ground waypoints.
You can download the data yourself to do whatever you want with it. Perhaps make yourself a very cool, high-res 3D model of the earth.
It's not clear how accurate the data is. The reports seem to say within 9m vertical accuracy. But I assume this is measuring the "surface" that the Shuttle saw - so that would include roof tops. But with smoothing/filtering, would this be washed out to represent an average 'ground height'?