Is the charge simply usage-based (" pay per click "), or does the charge have to consider the quality of service achieved (for example, response time)?

收费是基于使用情况(“单击一次收费一次”)，还是必须考虑服务所达到的质量(例如，响应时间)？

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Mobil will pay on a per-usage basis that gives it the coverage it needs in high-demand summer months, while costing little when business drops in February.

FORBES: Magazine Article