I've got a spreadsheet and a web browser open and I'm doing some research. I keep having to click back and forth. It'd be a lot better if I could take notes right on top of the web page, maybe have the spreadsheet transparent on top of the site I'm looking at.
1. Does anything like this currently exist?
2. If not, how hard would it be to do technologically?
I'd use it. A lot, actually.