[For demand side platforms,] is it the optimization of the bids, the allocation of budgets, managing potential conflicts between advertising campaigns from multiple customers and buying data? Or is it more related to other issues such as customer relations and getting ad networks out of competition?
This question was asked on Quora.com, below is my answer.

Mature Demand Side Platforms (DSPs) have conquered the primary requirements to being in business in the online ad space, including: campaign pacing, optimization of bids, campaign goals and budget allocations.  The old guard is now well established.  New DSPs, presumably with novel approaches to the market, may encounter some of these basic challenges.  There are a lot of examples they can look at in the market for guidance.

Ongoing challenges for all demand side platforms include things like the share of the customer’s budget.   Many advertisers are using more than one buying platform; whether those are multiple DSPs, ad networks, direct campaigns or other types technology platforms.  DSPs must present unique opportunities to customers.  This practice can lead to feature wars.  DSPs need to maintain parity with competitors and present novel offerings to customers to increase or even just maintain the budgets from those customers.

Even with the technology wars waging, companies operating demand side platforms must also maintain good relationships with their customers, even if they’re offering a self-service platform.  Sales and support go hand in hand in the online advertising world.  No one going after significant budgets gets a free pass.  Balancing the resources allocated to particular customers can be challenging in this business, like any other.  Conflicts between advertising campaigns, however, seem unlikely given the volume of inventory available on most platforms.  The human element can make adjustments if they arise.