Why does Google show multiple results from the same domain? [video]

In Google’s latest Webmaster Help video, Matt Cutts discusses about multiple results from the same domain, and how Google handles them in its latest Webmaster Help video. Specifically, he responds to the following user-submitted question:

Why does Google continue to present multiple results from one domain on a search result? (Does it really benefit the user to have 7 results from Yelp?)
Blind Five Year Old, SF, CA