marking text while reading ebooks

[Kamaraju S Kusumanchi <kamaraju@bluebottle.com>]

This question seems very rudimentary. But since I could not find answers
anywhere else, I thought I would just ask the experts here.

While reading a hard copy of a book, people usually highlight important
points with a sharpie, so that the important concepts can be glanced
through at a later point of time. Is there any analogous facility while
reading ebooks/articles on a computer? Say for example, I have a pdf or a
long html file with me. Is there any program which can highlight parts of
text and save it in the new state?

thanks
raju

-- 
Kamaraju S Kusumanchi
http://www.people.cornell.edu/pages/kk288/
http://malayamaarutham.blogspot.com/