In all the noise about MapBox's Series B offering and their successful bid to replace MapQuest's in house map rendering capability, it seems that our dear trade rags missed something.
Likely the most important medium term aspect of the successful bid is that it removed funding and support for a competing vector tile rendering stack that MQ was developing internally.
Anybody that has been following the developments knows that while open source and in principle freely available, the MapBox vector tile stack doesn't work "out of the box" in any reasonable meaning of the words. It follows the trend of the bits and pieces of MapBox's technology becoming increasingly more difficult to use in practice by the community. The other well known example is MapBox studio, the follow up to the widely independently used TileMill.
A recent article actually points to parts that are closed source, a not completly unexpected change of direction.
Now I think we all realize that it is just a matter of time till the open source community catches up on the vector tile front. This will address some of the issues the OSM community has been having with its map rendering and even the playing field a bit. But MapBox has clearly bought themselves some more breathing space for now.