I am trying to understand their business models. I am an Angle guy, not a techie.
In layman terms, how is Mapbox innovating?
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Sign up to join this communityMapBox provides a SaaS product. It has a free tier to get you in, then has clearly defined cost structures for bigger, better, stronger services. They innovated by making Open Source tech easier and prettier. MapBox's limitation is that it really only maps interactive maps. It doesn't do data storage and editing.
Google Maps has a nice API and make regular maps simple. Google Maps Engine is going the next step and getting close to a spatial data infrastructure. GME does data viewing, data downloads, and they have set up integration with other software, including ArcGIS, QGIS and FME to get data in and out of GME. What they don't have is clear licensing. Their prices are aimed at the high-end, enterprise level.
ArcGIS Online is a funny one. They try to do everything, but to do it propertly you really need to buy into the whole stack and use ArcGIS Server + Desktop + Online. They do have a point-and-click web interface for beginners and have lots of example maps and basemaps and everything. It does a lot of things. But, ESRI are really good at charging you money, and their pricing model is strange, in that you buy credits and they get consumed by doing things like rendering basemaps, views of maps, geocoding etc.
To answer your core question though, MapBox are innovating by shaking up the GIS world through the use of new, simple software (like TileMill and Leaflet) and data formats that are very different (MBTiles and TileJSON). And they do the modern web thing of providing a free service with all the functionality of the next, paid tiers, and the paid tiers are cheap, as compared with the incumbent, corporate/enterprise solutions.