Because MerchantCircle gets so much traffic from SEO in search results this will also be a major SEO play for the SMB that is the mayor of his/her particular city.
Merchant Circle has long been a favorite of mine and other local marketers for its ability to rank profile pages for a variety of local queries. Using the Barnacle SEO technique (so coined by Will Scott of SearchInfluence), pages on Merchant Circle and similar directory sites can drive a lot of free leads if you know how to use them.
I like the SMB gaming element here because to date the problem a lot of local directories have is with attracting advertisers and once attracted, getting them to engage with the service. By giving the merchant an incentive to network, Merchant Circle has the chance to get their hardcore users to do a lot of the heavy lifting for them. Seems like it could be a win-win scenario.