Historical clue formulations

• Online crowdfunding platform — 2026-06-10
• Site of many pitches — 2020-01-18
• Crowdfunding site ... or a hint to the beginnings of 17-, 30- and 46-Across — 2019-01-28
• Money source since 2009 — 2015-07-17
• Modern kind of campaign — 2014-10-18