31. A method for automatically annotating a video in a computer system, comprising: iteratively extracting video features from a received video on different spatial scales, wherein the video features comprise visual characteristics associated with the tiles of different sizes in an image within the video; matching the extracted video features to known video features; identifying other videos with similar video features to the extracted video features using one or more combinations of the matched image features; obtaining text associated with the other videos, wherein obtaining the text associated with the other videos comprises obtaining text that surrounds each video in a web page in which the video is located; identifying one or more intersecting keywords in the text associated with the other videos; and annotating the received video with the intersecting keywords using the computer system.
36. The method of claim 31 , wherein iteratively extracting the video features from the received video involves one or more of: generating color histograms; generating orientation histograms; using a direct cosine transform (DCT) technique; using a principal component analysis (PCA) technique; and using a Gabor wavelet technique.