at first, i wouldn't know that reading eBook can be fun.
'cause
first, eBook usually in english.
second, my english is very - very poor, either grammar or vocabulary.
third, sometimes finishing a real book really - really takes time, can be a day or months, cannot predict -- imagine how much time for me to finish an eBook.
right click on the unknown word, select synonyms, voila! if you lucky it will list synonyms for that unknown word.
if you had a nice internet connection, you could select look up then you can go through thesaurus.
other nice thing about eBook, you can transfer it into your other gadget. and read it there.
later i install thesaurus application on my palmheld, although not as easy as using microsoft word, it help.
the minus points of eBook is,
since you might get it from unauthorize ...umm.. souce.. , sometimes the quality of the eBook is not good, let say if it's OCR-ed version of hardcopy books, then sometimes there are misspelling or funny character that you might found irritated.
and. sometimes reading eBook could cause a twingy feeling in your eyes 