More #WP20 perspective:
2003 – WP born.
2004 – #bbPress
2005 – #automattic
2006 – ModernTribe
2007 – Contact Form 7; WPML, GravityGorms
2008 – WebDevStudios does WP; #BuddyPress, WooThemes
2009 – wpbeginner, Pippins Plugins
2010 – Yoast, Human Made
2011 – 10up, #WooCommerce