And the other sponsored ad is the same like for getting referrals, nothing new if you read my previous post about the reply of the new owner from EntreCard, Andrew Te (at the end of the article).
If you like, you are allowed to disable ONE of these ads. Just look in your Dashboard in the middle on the right side it's written in bold letter "Sponsored ads". There you can uncheck one of the green circles!
MORE EXPENSIVE to OPT OUT:
EntreCard will charge more money if you pay the Opt out-fee monthly :) Instead of 4,17 $ they charge you 5$ per month which results in 60$ per year. The yearly charge still remains at 50$. But i doubt anyone wants to pay 50$ in advance at it is not sure, if the ad service will be stable and profitable until next year.