I’ve marketed quite a lot through Stumbleupon (crowdsourcing service), usually I’ve pulled quite constant traffic of 2-3 thousand visitors per day and campaign (for both paid and unpaid campaigns).
Now it happened unintentionally with this product:
Well over 25 000 visitors from Stumbleupon and Reddit over the span of 36 hours, I was quite surprised.
Granted the kind of product above does not really sell however the spillover to other products was quite good.

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