The most significant change to OpenStreetMap in its immediate future isn't technical, but legal. The license used for OpenStreetMap's data is likely to change in the near future, and may have already changed by the time you read this.
At the time of writing, OpenStreetMap uses the Creative Commons Attribution-Share Alike 2.0 license (CC-BY-SA) for its data and map tiles. The intention of using this license is to allow use of the data for any purpose, by anyone, without further approval or permission, while requiring those using the data to make it available to those they distribute it to under the same or similar licensing conditions.
The terms of the license also prevent the data from being combined with an existing proprietary dataset without the resulting dataset being available to the contributors to OpenStreetMap. Some within the OpenStreetMap community feel this is necessary, because while OpenStreetMap's data is accurate and up to date, it's not complete...