NEW YORK (TIP): For years, the tech billionaire Pierre M Omidyar has been experimenting with ways to promote serious journalism, searching for the proper media platform to support with the fortune he earned as the founder of eBay. He has made grants to independent media outlets in Africa and government watchdog groups in the United States. In a more direct effort, he created a news website in Hawaii, his home state. Then last summer, The Washington Post came calling in its pursuit of a buyer. The Graham family ended up selling The Post to a different tech billionaire, Jeffrey P Bezos of Amazon. But the experience, Omidyar wrote on his blog on Wednesday, “got me thinking about what kind of social impact could be created if a similar investment was made in something entirely new, built from the ground up.” Omidyar also confirmed that he would be personally financing a new “mass media” venture, where he will be joined by journalist Glenn Greenwald of The Guardian, the British daily.