This is a good supplement if you're interested in the free vs. not-free debate (aka M. Arrington vs. 37signals). The concept of "mental transaction costs" -- the "cost" associated with making a decision of whether something is worth paying for and how much is it worth -- is a useful one. For me personally, if I decide something, particularly an online service, is worth paying for at all, I'd probably just as soon pay $20 as some fraction of a penny. In other words, if it's not free and it's claiming to add value to my life, it had better be adding at least $20 worth and convince me as such. Then again I've never given much thought as to what micropayments would be good for, so counterpoints are welcome.
I've recognized this 'mental transaction cost' for awhile, but never been able to put it into words. The article does a great job of it.
i think the answer lies on how you design the charging system. if users have to through a cart/transaction system, micropayments would never work. it should be simpler (say, with one click) with as less friction as possible.
micropayments are good for microservices. say you want to use basecamp for 1 week but dont want to pay the monthly service. itunes music store is another "microstore".