You may remember the full featured, unpublished API from popular mobile photo sharing site Instagram that we covered last month. The interface was reverse engineered by a developer and today Instagram asked anyone using its private, unofficial Instagram API to stop. At the same time, it announced a beta public API would be coming soon.
If you want to see in realtime what's going on Digg you can use their digg spy page. This popular Digg feature uses a dynamic Ajax UI to let you see diggs as they happen. And now it serves as a model for a growing number of mashups that use web APIs to give you a realtime window into activity on a variety of services.