Historical clue formulations

• Environmentalist's goal for harmful emissions — 2022-12-16
• Competitor of 21-Down — 2021-01-28
• AOL alternative — 2017-07-30
• Online option since 1998 — 2011-06-22
• Yahoo! competitor — 2008-12-04
• EarthLink alternative — 2007-11-12
• AOL alternative — 2006-10-29
• Popular Web service provider — 2003-07-27