I've been playing with Amazon's S3 for a while, but tonight I had a blinding flash of the obvious. To get higher levels of bandwidth, uptime, and reliability for Feed Digest (although they're pretty good already), all I need to do is render digests every 5/10/15/whatever minutes, push them to S3, and make users grab those versions. That way Amazon deals with the heavy bandwidth traffic, and the FeedDigest servers just deal with rendering and pushing digests to S3. I've no idea why this didn't occur to me sooner, especially since I have been planning a 'push' system like this for a while now.

Request levels are currently in the 100-150 million per month range, so I'm planning to test this system with a few beta testers first, but if S3 can stand the heat, this could be a great way to push FeedDigest's capacity up into the stratosphere. I need to see capacity of 1 billion requests per month next (peanuts, really, as Google dishes up over 30 billion per month, and FeedBurner about 8 billion per month).