[andr]

Hypothetical case study:

You want to host a liveblog for the Apple keynote at Macworld. No matter if you are a small site or Engadget, your traffic for that 90 minutes would be 2x to 100x bigger than your daily average.

So do you:

a) buy or rent extra servers for the whole month, spend a few man-weeks (or pay somebody for) setting them up, working on their synchronization, etc.

b) write a small script that regularly uploads the static liveblog HTML (or JSON) to an S3 dubomain and rely on Amazon's thousands of servers and flexible scaling (Dynamo, which powers S3, will allocate as many servers as needed to handle your load) to do the work?

Granted, option b)'s per-GB cost would be a bit higher, but your fixed cost for labor and hardware in a) would be even bigger.