I think to an extent that depends on how much effort/funds the devs are willing to put in to keep sites online. Say 100k people want to come and have a look on the 12th. ~1/10 of those would create accounts, if the server falls over at 11am and stays down then only 10k people will see the site, maybe 1k sign up.
If the server is up all day then I think you'd see much larger adoption.