Usability 
Depending on who is doing the counting, DailyMotion is either the number two or three user generated video sharing site (after YouTube) in terms of traffic.
The Dailymotion mobile site lets you search or browse though videos in subject area "channels" Or you can jump right into the "Most viewed", "Most recent", "Most popular" and "Best Rated" lists. It looks like the mobile site only contains a subset of the videos on the desktop site though. I was unable to find many of the videos that are on the main site.
The streaming (there is no download option) videos are in a rather low quality, low resolution (176x144) format even on phones that are capable of handing much larger and higher quality content like my Nokia N95. The only exception seems to be the iPhone which has a dedicated URL, iphone.dailymotion.com with full screen 480px wide videos.
You do not need to register to watch any of the videos. If you have an account you can log in to view your favorites and profile.
The only mobile upload option is with Shozu. Which is a great program, provided your phone supports it. It would be nice to see other mobile upload options like MMS, email and browse for file.