[nacker_hews]

It would be cool to further break this down by time of day. i.e. look at people who use IE8 from 9-5 on weekdays vs. the weekends. Because I bet nighttime weekday IE8 usage dampens the effect.

[edent]

Timezones are a problem there. Unless you're a hyper-local site, your worldwide visitor numbers will skew anything on a "daily" basis.

For example, my blog is based in the UK but gets a substantial proportion of visits from the USA - which itself has multiple timezones.

[tbirdz]

Couldn't you do some kind of correlation from geolocation to correct for time zone differences?