YouTube claims that this new service will allow you to determine trends in how long it takes for a video to become popular as well as what happens when they do become popular. Advantages vary for the different groups that will be using Insights. Creators will benefit from looking at viewing trends, partners can use the data to better understand their audience and become more profitable, and advertisers can tweak their marketing strategy based on past trends.
There are, without a doubt, people who are going to benefit from the addition of this new service, but there is one thing we have to remember. Most of the people who are on YouTube are there to watch the videos, not to create them or advertise there, so the effect of this announcement will not be immediately apparent to most YouTube users.
With all of this in mind, I think that this is an interesting look at video trends, but I'm not convinced that this is a game changer. It may help us to better understand the life cycle of web videos, but I think that this will ultimately be a bigger deal for partners and advertisers than it will be for content creators.
You can get a look at this new service by going to Account > Videos, Favorites, & Playlists > and then clicking on "About this video" for the video that you want to analyze.