Movies.yahoo.com, took some liberties in proclaiming Delgo the least successful film ever in only 3 days. Animated movies do tend to have a longer shelf life past opening weekend and the drop-off should be lesser.
It's also worth noting that Delgo beat oscar contenders Doubt and Gran Torino.
The key to it? Delgo opened in 2,160 theaters so it's per screen average was incredibly low, only $237. The article suggests that at $237 per screen, assuming it was 5 showings a day at the average ticket price, you'd have something along the lines of 2 people seeing it per showing.
First off, a steady stream of two people per showing isn't that bad, I've seen worse. I'd also imagine since the primary audience was children, that more people saw super-discounted morning showings or matinee which would be cheaper. Lastly, it was such a crowded weekend with Day the Earth Stood Still, Gran Torino, and Doubt coming in, that I doubt Delgo got four showings a day.