Update all messages in an old phpbb newsgroup what happen after ?

Hi to all,

Just clean an old phpbb forum i have, some messages are very old (more than 2 years) so i update (change content and ping the message) of course i close my id session.

So what's the futur ?

1- good all your pages would be re indexed as quick as search engines come back
2- you lose your time make new every day slowly is better than update all messages ?

thanks enjoy.
:cow_yello