1) A free lightweight, yet powerful screenshot and screencast (or screen recording, screen video, whatever you want to call it :) ).
2) A free hosting service to host those files that you create or get this - pretty much any other types of file!
The goal as outlined on the website seems to be "improve the way we communicate and converse" and make it more visual. It's nothing new really, I've been using the products of the company that is behind this - Tech Smith and love them....however I still use the jingproject because it's lightweight, and super easy to use, the whole thing is done very quickly, from captruing a video or screencast and publishing it to the web for your to share. HEck... they even place the link in your clipboard for you so all you have to do is paste it
wherever you need to - emails, IMs, website - wherever.
I've been using this myself to explain things to people that is sometimes hard to explain with words, it saves time and frustration from both parties. It can also be used as "visual proof" of whatever it is y want to prove. A picture is worth a thousand words like they say but a video is worth probably a few thousand words :).
It's also excellent to teach things. It's always much easier to learn by example and following steps that you see visually happening in front of you than trying to follow written instructions.