Also, on facebook, how many more people are going to get to see your wedding photo's than if just an album was printed and put in someone's loft?
I think you underestimate the magic of print - and its reach.
In my opinion, the couples still want to share a special moment like their wedding personally. So they won't dare to satisfy their photo-hungry friends with a lame album in the internet. They invite all their friends to their house and take a look at the photos together
- even if 90% of these guys are facebook addicts.
But to answer your question:
If the couple has 75 friends on their wedding and 75 friends on facebook - well, i think the amount of the people who will see the album and who will see the photos on facebook is basically the same.
And finally: what will leave a bigger impact at potential customers a.k.a. future wedding couples?
a) a facebook album
b) a nice printed photo album
It's not hard to find the answer.