This paper states the obvious for all of us who deal with remittance numbers on a daily basis. The sudden growth in remittances is indeed explained only by the change in the methodology remittances are recorded. However, due to the lack of the data prior to this change, we still need to deal with what is available. Indeed, with reservation, and no connection to any other factors which affect remittances.
The question is: where do we go from here? Remittance data is still poor, most of the developing countries do not publish any records and we have to rely on estimates and qualitative research. As a market researcher working for money transfer company, I struggle with figuring out the right estimates very frequently. World Bank is doing a great job in recording remittances, however, all countries which do not publish remittance data in their Balance of Payments are excluded. And in some countries, as rightfully pointed by David, remittance numbers are overstated.
Looking at the remittance numbers as a basis for quantifying economic growth or decrease in poverty is approach that should be avoided. Helping countries in figuring out how to better record their remittance numbers should come first.