Members of the Foundation are entitled to vote in the affairs of the Foundation. They have no special say in how the OpenStreetMap project is run, just the running of the Foundation. Anyone who wants to influence the activities of the Foundation is welcome to join.
As of 12th November 2009, the Foundation has exactly 265 fully paid-up members.
Full membership is available to all. The membership fee is £15 per year and enables you to influence the direction of OpenStreetMap by being able to vote in elections for officers of the foundation. Members may also get discounts on some OSMF organised events (such as the State of the Map conference). You do not have to be a member in order to use or contribute to OpenStreetMap.
Full membership may be initiated here.