This site uses Oracle, not MySql. The database crash is unrelated to the dns ddos attack, if anything this would relieve traffic on the site. At any rate, important points to be learned are:
that the quality of the service in an ideal situation has nothing to do with the internet today. Holding together a service like Mydomain.com requires a big investment in time on the networking front. If you don't have everything together, things can fall apart real fast.
when the database goes down on an installed version of ACS/OpenACS, why not bring up a maintenance page instead of the installation page, and send an email to an admin?
have a separate network connection to get to your machines in case of failure. Having a direct frontal attack on you network, should not affect your ability to login to your machines from the backend. I'm pretty sure the ISP wasn't affected by the ddos, otherwise they would have responded faster to the need to filter, implying that a backdoor could have been available.
tell your customers what is going on, asap. Otherwise you look like a jerk that either doesn't care or can't figure out what to do. The amount your customers pay for your service is irrelevent, the fact that they are using your service is enough to require you to think of their needs. If you can't do that, email the customers that you are getting out of the business so they can make other arrangements.
