Paid Discovery campaigns on StumbleUpon just became a whole lot smarter. The social bookmarking application just introduced a new feature called “interest optimization” to help advertisers target the right audience with their paid advertising campaigns. Until now, advertisers on StumbleUpon had to manually select interest categories, which make a big impact on how your campaign performs. StumbleUpon's audience is segmented according to interest.
The new functionality “interest optimization” will optimize your initial selection to match your campaign with other relevant categories after the campaign has launched. An advertiser, if they prefer, can strictly limit the campaign only to their own selected categories by turning off “interest optimization.” The new functionality is not forced upon advertisers.