Generating more external research citations via Google Scholar will help validate the World Bank's mission of informing policy debates. If 87% of the Bank's work goes uncited, Google's tracking tools can reveal which ones are cited by correlating language, page count, subject matter, and other metrics. Publishing in PDF should not be a limiting factor. I have seen plenty of academic material circulate in PDF copy because it successfully finds and audience.
The World Bank's social media and knowledge management people need to talk about content marketing. Google searches for marketing PDF content in social media reveal plenty of free guides from Marketo, Adobe, and other sources that want marketers to succeed. Has the World Bank ever cross-published its conference presentations to SlideShare? They should try it. It works. Have they ever completed a market analysis of the demographics that attend their conferences and request reports? Their depressing analysis of download stats may the first step.
I suspect the World Bank's problem lies in its inability to meet a market need for solutions. It acts like a bureaucracy that expects its captive customers to walk right in to its Open Knowledge Repository. The audience won't come if they don't know how the portal's products will benefit them. Private sector marketers know they must push media to a target market. The World Bank's content can solve the world's problems if it can push relevant content to an audience that needs it.