doubt about mode hooks

[Luca Ferrari <fluca1978@infinito.it>]

Hi all,
so far I've added mode hooks with something like the following:

(add-hook 'c-mode-hook (lambda()
                          (my-function-hook) )

but then I come across a snippet that does something different:

(setq my-personal-hook 'my-function-hook)
(add-hook c-mode-hook (lambda ()
          (run-hooks 'my-personal-hook) ) t )

so I was wondering what are the differences and which advantages
should I get using the second. I cannot see any particular advantage
from the manual, so I'm guessing the second effectively does not add
the hook itself, rather a function that runs the hook.
Any explaination?

Thanks,
Luca