Excerpt...
As we move into social media, the additional targeting options available within LinkedIn and Facebook can provide benefits that search marketing alone can't deliver, but there are tradeoffs, including losing the comforting keyword list you've used for targeting within search. Social media targeting is based on the person, her profile, and internal behavior (within the social network). Display ad retargeting and use of display advertising against behavioral cookie pools is another great supplement to PPC search for the B2B advertiser.
This is a good post that provides some direction on the differences between Search PPC and Social PPC, and how to manage the differences, especially the landing pages. Not a great deal of detail, but enough to provide you with thought as to how to attack the gap.