4. The method of claim 1 , wherein extracting the advertisement keywords from the digitized text is preceded by converting the audio-visual advertisement into digital text.
4. The method of claim 1 , wherein extracting the advertisement keywords from the digitized text is preceded by converting the audio-visual advertisement into digital text. 7. The method of claim 4 , wherein converting the audio-visual ad comprises performing optical character recognition on an image captured from the audio-visual ad.