over the mobile phone is different - it is personalized and targeted. Research by the Boston Consulting Group shows that 70 % of consumers worldwide are positive towards receiving targeted advertising. This is true if they get some kind of incentive in return, for example free airtime or cash incentives. And, there is money in advertising. The market for online advertising is growing faster than advertising in any other media. Operators can get a piece of the cake by acting as advertising brokers. Advertising also encourages follow-on voice calls, with more revenues from additional traffic as a result. Payment Transaction Handler The payment transaction handler provides secure payment services for e-commerce trans- actions on the Internet. The handler manages also the financial aspects of transaction handling in a standardized way, also taking the financial risk. In the grocery case the operator could charge the end user/buyer for her/his purchases together with the telecom bill. VISA is another player in this role. The transaction handling is similar to traditional signalling schemes. However, all communication is IP based. See Figure 4.23. Note that payments can also be arranged through the credit card company instead of e-Pay. Apart from all these communication and content-oriented roles there are in fact other types of role. Telecom Business 1. View time table 2. Order ticket GSM 1 3. Make offer 4. Present offer/ Password request 5. Password reply 6. Payment transaction request 7. Payment transaction confirmation 8. Payment confirmation Train: 9. Confirmation of ticket reservation Time table Mobile and payment Journey planner GW e-Pay Ticket reservation Your reference Mobile operator # 8364A2 service network Train company London Paris Today network Departure time 10:45 Arrival time 11:55 One way Credit card Paid via Credit card 1 adult, window seats company network WELCOME Figure 4.23 Payment transactions, example Example 1: The retailer role. The retailers focus on the relationships with the end users: subsc