The Geocodio Reverse Geocoding Ruby Sample Code demonstrates how to access the API to convert latitude and longitude into a street address with reverse geocoding. Geocodio will find matching streets and determine the correct house number based on the location.
Flickr has added more real-time goodness to their photo API. Using a publish / subscribe (PubSub) system, developers can now receive real-time updates across millions of photos across Flickr friends, Flickr Commons, and by tags and geo-location using the Flickr Real-Time API.
In late March, Google announced enhancements to their mapping API that gave developers programmatic access to their popular streetview feature. Now there are some very interesting streetview mashups to check-out.