This module enable Feeds to take in data from a view output (i.e. from Views). This combined with pluggable query backend in Views 3.x will enable Drupal to import data from practically anywhere from the web given the Views pluggable query backend is implemented.
There is a screencast showing on one thing that this module can do (Importing Twitter Tweets into Drupal using Views and Feeds).
For further documentation, refer to Advanced Help page of this module.
This project is sponsored by Google Summer of Code.