That is the Ad Pack, which can be seen in the Advertise tab -- if you are a potential advertiser that wishes to promote a product or service, you'll need that to show your advert ( advertisement ) in ClixSense ( as seen on Advertise on the ClixSense Network )
Other references can be seen over at:
HelpDesk FAQS -- What are ad credits used for?
HelpDesk FAQs -- What are the differences between all of the ad exposure types?
HelpDesk FAQs -- What are ad credits, can I get more ads with them?