I'm not convinced they hit the 100,000 mark, or even came close. Two reasons, one is what I stated above, and 2, the lack of photographs of the throngs of people that would have been there. Normally, when that many folks show up you get the wonderful roof top shot of the throngs, I can't find one anywhere. Instead, close ups of groups are what are on all of the websites.
Of course the star of the show was Commander-In-Grief, Cindy Sheehan, you remember her, right. The lady who's son enlisted (voluntarily) in the Army, then re-enlisted, voluntarily during a war, then volunteered to go on a mission, and was killed. Yeah, that's the lady, the one who says it's the President's fault her son is dead. All the pictures of her were close up shots of her and a dozen or so people, again, leading me to speculate that the turn out wasn't nearly what they hoped for.