[tnator]

While the data is interesting, are we really sure Walmart.com availability was 91%? If that was really the case, it would have been covered more widely, don't you think?

[bbali]

Walmart had their share of issues: http://adage.com/article/cmo-strategy/amazon/299506/

Side note: AMZN just announced profits, perhaps time to buy WMT ;-)

[goPro99]

I ran into at least 1 error page on AMZN that day and their availability is captured as 100%.

[goPro99]

If they are capturing only 500 status code and not soft failures (which might be amazon's case), that could explain 100% availability.