SW for making notes on reading text file.

[john_re]

What's great sw that enables commenting, underlining & highlighting in
colors onto text or html files?  Like what one could do while reading
print materials - magazine or book?

So, I'd like to use this on a web page with any "article" like text. &
also on regular .txt plain text files.

Anyone use this currently?  I'm thinking today's college students, who
are doing lots of reading, & likely more & more computer downloaded
material, might be a large category of users for this.