Just wondering if there's anything such as rating for manga. Not like the kind where you measure how good it is but rather what age it shall be appropriate for. or for that matter, what about Anime as well?

Only on the ones they sell in stores. Would't know how it is in Japan though... and well genre usually covers that i'm guessing. Seinen for example is for the older crowd as is mature, ecchi, hentai, adult.

why back in the day we didn't 'download', we had to swim to japan if we wanted fresh anime and that was only if...

I dream of a better tomorrow... where chickens can cross roads and not have their motives questioned.

There are target audiences, yes. We don't really list them here on B-U, although we do have the "Mature" and "Adult" genres, which help a bit.