M2 is money in the form of traverlers checks, regular checks, e-money, and similar forms of secondary money.  It is peculiar to see that the total number of deposits made is more than the amount of currency available.  E-money is harder for banks to track, especially when they are in the hands of third party business such as Paypal.  If the central banks underestimate how much money is flowing through the economy, the government will think to print more money, which would cause inflation.

Another major challenge for e-commerce is to deal with different cultures and rules from different countries.  Ads for war toys like these are banned in Greece, but not in the U.S.  If this ad was shown on a website hosted by the U.S. and a citizen from Greece happened to find it, that citizen could file a court order to have the company in the U.S. take the image down.  The question is, does the company in the U.S. have to comply with Greek rules?

As e-commerce becomes more popular, consumers become more susceptible to cyber-crime.  In this cartoon, a man is pretending to be from the utility company and would like to confirm important information.  In some cases, scammers already have information such as a potential victim's social security number and credit card number simply by using the internet.