The use case: sometimes I need to read long articles in HTML format. For example: the HTML5 spec in a single HTML page. As I progress through the article, I want to be able to selectively delete parts of it. I wish to do this so that when I re-read the article later on to understand it better, I could skip over the parts I don't need to read again.
Ideally I would like to just be able to open the HTML page in a browser and have basic notepad like text editing capabilities (select text, hit delete). However, I don't mind having to copy the HTML page into another program, as long as that program perfectly preserves the article style (for example, when I copied the HTML5 spec into Microsoft Word, some of the section highlights did not transfer over. That is a problem for me).
I'm using both Windows and Linux. My main browser is Firefox, but I have all the major browsers installed.