For me the big ones have been: - Adobe - Equifax - Zappos (prior to their acquisition by Amazon) - Gizmo (defunct VoIP service aquired by Google) - Tumblr

For me the big ones have been: - Adobe - Equifax - Zappos (prior to their acquisition by Amazon) - Gizmo (defunct VoIP service aquired by Google) - Tumblr - Amazon (though that's likely via a seller)