friendfeed was built in 08, before amazon had released EBS as a feature. there is no way in hell the instance-store disk i/o would have kept up with friendfeeds mysql demands (you may remember the post Bret himself wrote on their nifty approach to mysql: http://bret.appspot.com/entry/how-friendfeed-uses-mysql ) Frankly, even EBS probably wouldn't have. Plus, back in 08 the larger ec2 instances were still pretty low on ram compared to what you could cheaply cram in a colo'd server, putting even more pressure on the disk i/o.

I think Bret's really wishing what almost everyone is, that these problems would just go away and you could pay a reasonable premium for that, but we're not there yet and certainly weren't in 2008. I don't think he really checked his numbers on this one.

edit: however there is a happy medium. managed service providers will gladly charge you ec2 prices (250/month for a low end server, 500/month for a beefy one) while handling all midnight colo trips for you.