【答案解析】People are paying more bills online and sending more e-mails instead of letters, so postal firms were once seen as obsolete. But now, the success of e-commerce requires large amount of delivery services. So post offices are "rescued". After four years of profits, the US Postal Service has cleared, its $11 billion of debt. E-retailers like Amazon and eBay have helped Britain's Royal Mail profitable. Germany's Deutsche Post now owns DHL, a big international delivery company.