> I think you misunderstood: the OP is saying that S3 was the only service that Amazon was actually using internally at the time out of the initial AWS service offering, even though AWS as a whole was sold as "the infrastructure that runs Amazon".
I can't even find sources of such a claim at the time the first offering of AWS occurred. The claim has made that as of 2010, 100% of amazon.com traffic goes via EC2 which I believe is likely as it has been mentioned by Amazon engineers.
That AWS was not built for amazon first and foremost has been said from the start. Jeff Bezos himself said early on that why only build it for themselves when they can sell it.
> I thought AWS started with EC2 & S3? Anyone got a link to a reliable history?
AWS's first service was SQS which launched two years before S3. EC2 launched half a year after S3.
There is a bit of history here: http://jeff-barr.com/2014/08/19/my-first-12-years-at-amazon-...
