I have a share hosting, and I charge 100$/year to host company websites. Those websites have a maximum of 2000 person per month access onto the site, mostly Wordpress. So everything is fine until a person in Facebook, with 300000 friends talk about the website. Even if just 10% go see the site, it's 30,000 people at the same time accessing the site and, the site crashed. Then after 1 hour, it's back on...
So the question, how best to cope with that ?