Which digital media should be managed creative agency side?

I understand the value of network buys and the economies large media companies can derive but there are some digital media types like Facebook and YouTube promoted content that should be managed by creative agencies. Heineken’s recent multi million dollar deal with Google [YouTube] is a great step forwards in brands achieving economies of scale with big digital media publishers that matter and this I think opens the door for the creative agencies to manage these channels. The reason for this is that with the two main media channels YouTube and Facebook being highly agile and optimisable it makes more sense for the management of these media to be done by the agency that makes the content [YouTube] and manages the communities [Facebook]. Further, I think with these two dominant and highly valuable media channels in particular the value equation for media buying and deployment has changed. These channels to me are more valuable than normal display networks for a number of reasons but one that I think that is highly valuable is their flexibility. YouTube promoted content for example is not beholden to a media schedule or limited inventory [yet anyway]. So the media plan around YouTube can be adapted multiple times over the course of a campaign. The integration with Google display to retarget to content viewers is also immensely valuable, and planning and optimising this media with data and analytics that creative agencies have would add vast efficiencies.

I would almost think these types of media are in a category that is distinct from display network media because they are more closely associated with a brands owned channels being YouTube channels and Facebook pages. And now with Google + I am sure Google and YouTube media will become even more closely integrated with owned channels being Google Circles.

I think the model should be this: clients form large scale buying agreements with Google and Facebook, creative agencies plan this media, manage the data, use and optimisation of these channels. Media agencies then continue to manage network buys to ensure economies with these networks. That way owned channel data and owned channel type media can be better integrated and deliver beter results.