eBusiness leaders can't assume that existing investments in data centers, bandwidth, and content delivery networks (CDNs) will be sufficient to ensure blazing-fast speeds in faraway markets or on shaky cellular connections. Optimizing an eCommerce site for performance on a global scale — while accommodating nuances in mobile — requires additional oversight, budget, dedicated technical resources, local expertise, and specialized vendor solutions. This is an update of a previously published report; Forrester reviews and updates it periodically for continued relevance and accuracy.