what rendle said.
i don't think its that useful unless you are developing some kind of web based application.
i'd also not do it unless you either know lots of JS, or want to spend a lot of time humming and hahing over why something doesn't work in IE when it does in FF.
I'm just curious about the technology to be honest.
I'm stepping away from web development* (in terms of my career) so I don't want to get involved, just want to know what it is.
*which sucks when I still owe £1,500 of my web designer course.