"Most importantly, maybe now bookshops and electronics dealers will realise that it's not so easy to rip us off anymore and may have to actually resort to cutting prices to acceptable levels to begin with."

In Japan, Amazon is one of the most expensive shops one can think of...

Google's had the price comparison feature for years.

http://www.google.com/intl/en_us/mobile/sms/#

Amazon will still rake in plenty of cash on the sales, though.