With Hijack you can add your artistic flourishes on any web page ! Of course, if everybody draws stuff all over the place then the internet will get a little messy. So, Hijack includes a sophisticated scoring mechanism and as your addition to the page gets judged (by other hijack users) it becomes more likely to be seen by those who would like it, and less likely to be seen by those who wouldn't.
With Hijack, you can chat and discuss things with other visitors to the site, without waiting for that website to add a forum, or finding another place online where people are talking about it. Say what you want, where you want.
Most forums give you an up arrow and a down arrow. We believe that human discourse deserves something more sophisticated than a binary choice (or even worse a 'Like' button). So, instead of up-voting and down-voting, Hijack gives you a 6 dimensional judgement space. It might be a little confusing at first, but play with it for 5 minutes and you will get it. (If you're not smart enough to understand it, maybe you shouldn't be casting judgement on others anyway.)