I don't know if you've had a chance to see it yet, but we've just launched on Monday the United Nations Global Pulse site at http://UNglobalpulse.org. First and foremost, this site acts as a web presence for the Secretary General's "Voices of the Vulnerable" report on the impacts of vulnerable populations and economic crisis.
The site also uses the OpenLayers module and MapBox tiles to accomplish its second goal: show these crises and the response of UN teams grouped by different projects (side note: big thanks goes out to Development Seed for their work on MapBox).
Because the report was announced in a general UN meeting that was picked up by the press, the Global Pulse team needed a very scalable server stack that could deploy quickly, so they chose Pantheon. In addition to being able to handle the jumps in traffic, Pantheon includes Apache Solr. The site runs Solr search because it is a great way to allow for a topic, document type & region-related faceted search.
We were really honored to work with the United Nations on such an important project. We'd love for you to explore the site, and let us know what you think.