Google Inverts Exchange Rates in AdSense Payouts
For the month of March, it appears that Google mistakenly inverted the exchange rate it uses for making payments to AdSense publishers in Canada, Sweden, Denmark, UK and a number of other countries . This means, for example, that if USD$0.88 is worth $1 Canadian dollar, Google paid Canadian AdSense publishers as if USD$1 = Canadian$0.88.
Google has been quick to address the issue, including sending remaining $$ owed. It's worth noting, however, that no overpayments seem to have been made; if that was the case, though, I don't expect those AdSense publishers would talk about it much on the forums.
Google outsources AdSense publisher payment processing, but I believe in this case the calculations are done by GOOG employees, not the contractor. In any event, heads will roll on this one, and it highlights the stresses that hyper-growth have put on Google's accounting systems, processes and personnel.