It's an important reminder that most startups are run by a handful of people who are normal, fallible human beings. They generally don't have access to the infrastructure and manpower required to be on the ball and maintain near 100% uptime of their services. I think the important information to be gleaned about a company is how they deal with problems like this (not necessarily the fact that they encountered the problem in the first place - if that is of concern, pick a more established organisation).

Also another issue, which probably doesn't apply to Parse is limited funding. One of my own venture's certificates has now expired and as a 'bootstrapped' web app, I simply can't justify spending more to renew the certificate. However I keep the service live as a demo to potential customers, if one takes a very keen interest I will happily renew it, or seek further funding.