VK, second largest social network in Europe, switched to MapBox maps September 1st. Its 47 million daily users now see their stories, photos and messages all mapped on MapBox maps. The switch from their previous map provider was fast, with the actual engineering work not taking more a few lines of code.
VK uses MapBox maps for large slippy popout maps like in this example of a locator map for a post:
This is the interface for attaching a map to a post on VK:
VK instantly adds a vast number of new OpenStreetMap data consumers, incentivizing a new audience to not only consume OpenStreetMap data but also to improve it. This is especially exciting in VK's case, as its core countries already have very active OpenStreetMap communities.