I was on EC2+apache+wordpress+mysql and had my blog go down as well after being featured on HN. In my case, simply rebooting the cloud instance fixed the problem (I had lots of other old projects running on the same instance). However, I did do some research into figuring out what I could have done as my blog kept getting more traffic ... had I used RDS, I could have gone to a bigger instance with little downtime. Unfortunately, my understanding is that there would be no way to go back down to a smaller RDS instance.
P.S. I upvoted you. I also don't get why people downvoted you.
P.S. I upvoted you. I also don't get why people downvoted you.