Here's a useful application for simple video editing - wevideo.com. wevideo is an online platform for collaborative video editing in the cloud. (What's "the cloud"? Click this link to learn more.)
There are a couple of advantages to this. First since weideo runs in a web browser you can work almost anywhere with computer access to the Internet. WeVideo supports HD and camera files can be uploaded from the field directly to your account - ready to edit.
And because it's a cloud-based system cloud computing system there's a significant workload shift. Your local computer no longer has to do all the heavy lifting to support the editing application. Finally WeVideo makes collaboration very easy. One can choose to share access to a project with other users, allowing you to collaborate across time zones or across town. Wevideo was also created with sharing in mind, so sending finished videos to popular social media sites is simple
That said, it isn't a perfect solution yet. The editing tools are fairly simple and lack some functionality but I expect those issues will be resolved as the application is upgraded.
So who is this for? I'd recommend it for teachers who want to introduce students to video editing. Video bloggers could also benefit from the service and I'd also recommend it to the casual home user for vacation videos or family stuff. I can also see it being a very useful tool to share footage and create rough-cuts from remote locations with your collaborators in other locales.