A business angel (also known as an angel investor, informal investor, funder, private investor, or seed investor) is an affluent individual who provides capital for a business start-up, usually in exchange for convertible debt or ownership equity. In WikiTalks you can learn a lot about this topic from many interesting speakers.
The most accurate definition of the open data says that open data presents data that can be freely used, re-used and redistributed by anyone - subject only, at most, to the requirement to attribute and share alike. The main characteristics of open data are: availability and access, reuse and redistribution, and universal participation.
Social entrepreneurship is the attempt to draw upon business techniques and private sector approaches to find solutions to social, cultural, or environmental problems. While conventional entrepreneurs typically measure performance in profit, revenues, and increases in stock prices, social entrepreneurs also take into account a positive "return to society".