My boss and I sat watching and waiting and we saw virtually no effect from the show whatsoever. (If you were just watching top on the servers without knowing Oprah was talking about it, you would have assumed it was any other day.)
We spent time theorizing why this was. We came up with the following:
- The site that we built has a relatively long URL, so maybe it was hard to remember.
- The bumper that the URL appear at was towards the end of the show, at which point we figured most stay at home moms/dads/people that watch Oprah were probably starting to get dinner ready.
- I'm not sure that people that watch Oprah are the same people that eagerly sit in front of the TV with an iPad/laptop/etc.
Of course, your mileage may vary. If you're using Rackspace, I'd say you're in good hands. It may be worth mentioning to them when it's going to happen and seeing what they can do in case of sudden load, but for us it certainly wasn't the huge gush we were expecting/hoping for.