I get that it shows a spike, my point is that I have no idea where it gets that data from. A quick read shows that it's based on people saying that their service is down - so you're quite likely to get people submitting a report saying Xbox Live is down when their Internet connection went dark, because the result was they got kicked out of a game. I wouldn't declare this to be a problem larger than Virgin Media based on that source, is what I'm saying.
My point is that asking people who call their Internet connection "my wi-fi" to correctly diagnose the source of any outage is probably not a fantastic idea if you're looking to accurately work out what is going on. There's comments on that site of people reporting a BT service outage when they can't log into their account, for example.