[pdftex] Tweaking pdf outputs to produce one box per word.

[CFP]

Hello everyone!
(I think this is where I should be asking, but I’m not totally sure
 Forgive
me if I'm mistaken :))

I’m trying to tweak the output of the pdflatex command to make it produce
one box per word. Consider this example:
    \documentclass{minimal}

    \begin{document}
        This is an example sentence.
    \end{document}

When opened in a PDF editor after compilation, this sample will appear as
one text box containing the sentence "This is an example sentence.". This is
fine for most full-featured pdf readers. Yet on my sony e-reader, selection
of words is based on boxes ; therefore my pdf reader will select the full
sentence, hence failing to find a definition for the word I clicked.

I noticed that pdflatex stops at punctuation marks. How can I proceed to
make it create one box per word? In the output, I would then have one box
for "This", one for "is", one for "an", and so on.

Thanks a lot!
CFP.