There is a lot of confusion in both the original article and this forum about what the Forrester researcher did and did not say. I am a Forrester subscriber and I've read the report so let me try to clear it up.
Forrester maintains a panel of 7,000 consumers who willing provide information about their technology habits, including their credit card purchases. No one snooped through people's credit card data. These people willing gave their information for study, knowing it would be kept confidential.
Forrester looked at transactions by this panel from April 2004 to June 2006. During this time there were 2,791 iTunes purchases by the 7,000 consumers on their panel.
Forrester also looked at the data from the perspective of "households," not just individual users. There were 5,580 households that remained part of their panel continuously from July 2005 to June 2006. During that 12 month period, only 181 of those households made an iTunes purchase.
Right away you should realize this isn't a very deep population sample. Apple has sold more than 1.5 billion songs on iTunes and this study only looks at a total of 2,791 of those transactions, spread out over two years.
Everything that Forrester says in this research about iTunes is drawn from this sample. The big headline is that the number of transactions, per household in their panel, went from about 17 in January 2006 to about 7 in June 2006, while the average amount of dollars spent on each transaction went from about $7 to about $5.50. This amounts to a 65% drop in monthly revenue during that period.
This was the first drop in the data that Forrester saw, reversing a generally upward climb since June 2004.
Forrester themselves cautioned heavily against people drawing larger conclusions. In particular, the report does not suggest that "iTunes monthly revenue droped 65%." It says the monthly revenue dropped 65% among the people it's been watching as part of its consumer panel.
It may well be that people get an iPod, buy some songs (not too many) and then stop buying after a little while. But if more people keep buying iPods and then buying songs that may prop up the revenue from the store. Of course, long term, that still bad news for the iTunes store but it's different that what's been reported.
