I guess the people who attended Barack Obama's announcement as a candidate for President drew more people than I could tell from watching the video. Taegan Goddard is reporting that the local police estimated the crowd between 15,000 and 17,000. I had thought the number to be about 4,000, but then again, I'm terrible at such estimates.
As for the speech, I thought the speech was very good, if not great by Obama standards. He does tend to set the bar rather high, by most other candidates standards it would have been a home run.
Here is the video