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Apple has today significantly opened up iAd Workbench, the tool used to submit and manage iAd campaigns. Ad Age notes that Workbench is now accessible to anyone with an Apple ID, where previously accounts were restricted to registered app developers. That should expose iAd to a more Google-like advertising base, in which anyone can participate; when it was originally introduced in 2010, iAd was targeted exclusively at major corporations able to afford the then-minimum buy-in of $1 million. New ad buyers can choose to operate on a cost-per-click or cost-per-thousand impressions basis….
